Optical occupant sensing techniques

ABSTRACT

Vehicular system for determining the presence of an object in a passenger compartment of the vehicle includes a first image receiver arranged at a first location for obtaining a first two-dimensional view of a portion of the compartment, and a second image receiver arranged at a second location for obtaining a second two-dimensional view of the same portion of the compartment, the second image receiver being arranged relative to the first image receiver such that three dimensions of the portion of the compartment are encompassed by the first and second views. A processor receives images from the first and second image receivers and determines whether an object is present in the compartment based on the images. A reactive system, such as an airbag assembly, may be coupled to the processor and controlled thereby based on the determination of whether an object is present in the imaged portion of the compartment.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is:

1. a continuation-in-part (CIP) of U.S. patent application Ser. No.10/413,426 filed Apr. 14, 2003, now U.S. Pat. No. 7,415,126, which is:

A. a CIP of U.S. patent application Ser. No. 09/765,559 filed Jan. 19,2001, now U.S. Pat. No. 6,553,296, which is a CIP of U.S. patentapplication Ser. No. 09/476,255 filed Dec. 30, 1999, now U.S. Pat. No.6,324,453, which claims priority under 35 U.S.C. §119(e) of U.S.provisional patent application Ser. No. 60/114,507 filed Dec. 31, 1998;and

B. a CIP of U.S. patent application Ser. No. 09/925,043 filed Aug. 8,2001, now U.S. Pat. No. 6,507,779, which is:

-   -   1. a CIP of U.S. patent application Ser. No. 09/765,559 filed        Jan. 19, 2001, now U.S. Pat. No. 6,553,296, the history of which        is set forth above; and    -   2. a CIP of U.S. patent application Ser. No. 09/389,947 filed        Sep. 3, 1999, now U.S. Pat. No. 6,393,133, which is a CIP of        U.S. patent application Ser. No. 09/200,614, filed Nov. 30,        1998, now U.S. Pat. No. 6,141,432, which is a continuation of        U.S. patent application Ser. No. 08/474,786 filed Jun. 7, 1995,        now U.S. Pat. No. 5,845,000;

C. a CIP of U.S. patent application Ser. No. 10/116,808 filed Apr. 5,2002, now U.S. Pat. No. 6,856,873, which is a CIP of U.S. patentapplication Ser. No. 09/838,919 filed Apr. 20, 2001, now U.S. Pat. No.6,442,465, which is a CIP of U.S. patent application Ser. No. 09/389,947filed Sep. 3, 1999, now U.S. Pat. No. 6,393,133, the history of which isset forth above; and

D. a CIP of U.S. patent application Ser. No. 10/302,105 filed Nov. 22,2002, now U.S. Pat. No. 6,772,057;

2. a CIP of U.S. patent application Ser. No. 10/895,121 filed Jul. 21,2004, now U.S. Pat. No. 7,407,029 which is a continuation of U.S. patentapplication Ser. No. 10/733,957 filed Dec. 11, 2003, now U.S. Pat. No.7,243,945, which is:

A. a CIP of U.S. patent application Ser. No. 10/116,808 filed Apr. 5,2002, now U.S. Pat. No. 6,856,873, the history of which is set forthabove;

B. a CIP of U.S. patent application Ser. No. 10/302,105 filed Nov. 22,2002, now U.S. Pat. No. 6,772,057;

3. a CIP of U.S. patent application Ser. No. 10/940,881 filed Sep. 13,2004 which is a CIP of U.S. patent application Ser. No. 10/116,808 filedApr. 5, 2002, now U.S. Pat. No. 6,856,873, the history of which is setforth above; and

4. a CIP of U.S. patent application Ser. No. 11/025,501 filed Jan. 3,2005 which is a CIP of U.S. patent application Ser. No. 10/116,808 filedApr. 5, 2002, now U.S. Pat. No. 6,856,873, the history of which is setforth above; and

5. a CIP of U.S. patent application Ser. No. 11/839,622 filed Aug. 16,2007.

This application is related to U.S. patent application Ser. No.08/474,782 filed Jun. 7, 1995, now U.S. Pat. No. 5,835,613, Ser. No09/047,703 filed Mar. 25, 1998, now U.S. Pat. No. 6,039,139, Ser. Nos.11/455,497 filed Jun. 19, 2006, 11/502,039 filed Aug. 10, 2006,11/538,934 filed Oct. 5, 2006, 11/558,314 filed Nov. 9, 2006, 11/558,996filed Nov. 13, 2006, 11/614,121 filed Dec. 21, 2006 and 11/619,863 filedJan. 4, 2007 on the grounds that they include common subject matter.

All of the above-mentioned applications are incorporated by referenceherein.

FIELD OF THE INVENTION

The present invention relates generally to systems and methods forsensing occupants in a compartment in a vehicle using opticaltechnologies.

BACKGROUND OF THE INVENTION

Background of the invention is found in the parent applications, inparticular the '786 application. All of the patents, patentapplications, technical papers and other references mentioned below andin the parent applications are incorporated herein by reference in theirentirety.

Possible definitions of terms used in the application are set forth inthe '881 application, incorporated by reference herein.

Preferred embodiments of the invention are described below and unlessspecifically noted, it is the applicants' intention that the words andphrases in the specification and claims be given the ordinary andaccustomed meaning to those of ordinary skill in the applicable art(s).If the applicants intend any other meaning, they will specifically statethey are applying a special meaning to a word or phrase.

Likewise, applicants' use of the word “function” here is not intended toindicate that the applicants seek to invoke the special provisions of 35U.S.C. §112, sixth paragraph, to define their invention. To thecontrary, if applicants wish to invoke the provisions of 35 U.S.C. §112,sixth paragraph, to define their invention, they will specifically setforth in the claims the phrases “means for” or “step for” and afunction, without also reciting in that phrase any structure, materialor act in support of the function. Moreover, even if applicants invokethe provisions of 35 U.S.C. §112, sixth paragraph, to define theirinvention, it is the applicants' intention that their inventions not belimited to the specific structure, material or acts that are describedin the preferred embodiments herein. Rather, if applicants claim theirinventions by specifically invoking the provisions of 35 U.S.C. §112,sixth paragraph, it is nonetheless their intention to cover and includeany and all structure, materials or acts that perform the claimedfunction, along with any and all known or later developed equivalentstructures, materials or acts for performing the claimed function.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and improvedmethod and system for obtaining information about occupants in a vehiclecompartment using optical technologies.

In order to achieve this object and possibly others, a vehicle includinga system for determining the presence of an object in a passengercompartment of the vehicle in accordance with the invention includes afirst image receiver arranged at a first location in the vehicle forobtaining a first two-dimensional view of a portion of the passengercompartment, a second image receiver arranged at a second location inthe vehicle for obtaining a second two-dimensional view of the sameportion of the passenger compartment, the second image receiver beingarranged relative to the first image receiver such that three dimensionsof the portion of the passenger compartment are encompassed by the firstand second views, and a processor for receiving images from the firstand second image receivers and determining whether an object is presentin the passenger compartment based on the images. A reactive component,system or subsystem may be coupled to the processor and controlledthereby based on the determination of whether an object is present inthe portion of the passenger compartment. The reactive component, systemor subsystem may be an airbag assembly including at least one airbag,one or more deployment parameters of which are controlled by theprocessor.

To enable the three-dimensional viewing, the first receiver may bearranged on an A-pillar of the vehicle, on a roof of the vehicle above aseat of the vehicle or on a headliner of the vehicle directly above theportion of the passenger compartment, while the second receiver may bearranged on a headliner of the vehicle at or proximate a center of aheadliner of the vehicle or on a headliner of the vehicle relative tothe portion of the passenger compartment. The first and/or secondreceiver may be arranged in a dashboard or instrument panel of thevehicle to receive an image reflected by a windshield of the vehicle.The first and second receivers may be one of the following: a CMOSdynamic pixel camera, an active pixel camera or an HDRC camera operativeusing a logarithm of incident light.

In one embodiment, the processor is arranged to process the imagesreceived from the first and second image receivers to subtract imagesobtained in the presence of artificial illumination from images obtainedin the absence of artificial illumination. The processor may also bearranged to process the images received from the first and second imagereceivers to form a three-dimensional image of a seat in the portion ofthe passenger compartment without an occupant present, process theimages received from the first and second image receivers to form athree-dimensional image of the portion of the passenger compartment whenan occupant present and subtract the formed three-dimensional image ofthe seat from the formed three-dimensional image of the portion of thepassenger compartment and then determine whether an object is presentbased on the resultant image. Further, the processor may be arranged toanalyze the images from the first and second image receivers over timeby comparing the images received from each of the first and secondreceivers at different time and analyzing differences between theimages.

A vehicle including a system for ascertaining the identity of an objectin a passenger compartment of the vehicle in accordance with theinvention includes first and second image receivers as described aboveand a processor for receiving images from the first and second imagereceivers and ascertaining the identity of the object based on theimages. The same enhancements to the system above can be applied to thissystem as well. For example, a reactive component, system or subsystemmay be coupled to the processor and controlled thereby based on theidentity of the object.

A method for determining the presence of an object in a passengercompartment of a vehicle in accordance with the invention includesobtaining a first image of a portion of the passenger compartmentcovering first and second dimensions of the passenger compartment,obtaining a second image of the same portion of the passengercompartment covering the first dimension and a third dimension such thatthree dimensions of the portion of the passenger compartment areencompassed by the first and second images, and determining whether anobject is present in the passenger compartment based on the first andsecond images. The same enhancements to the system above can be appliedto this method as well.

A method for ascertaining the identity of an object in a passengercompartment of a vehicle in accordance with the invention includesobtaining a first image of a portion of the passenger compartmentcovering first and second dimensions of the passenger compartment,obtaining a second image of the same portion of the passengercompartment covering the first dimension and a third dimension such thatall three dimensions of the portion of the passenger compartment areencompassed by the first and second images, and ascertaining theidentity of the object in the passenger compartment based on the firstand second images. The same enhancements to the system above can beapplied to this method as well.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of embodiments of the systemdeveloped or adapted using the teachings of at least one of theinventions disclosed herein and are not meant to limit the scope of theinvention as encompassed by the claims. In particular, the illustrationsbelow are frequently limited to the monitoring of the front passengerseat for the purpose of describing the system. The invention applies aswell to adapting the system to the other seating positions in thevehicle and particularly to the driver and rear passenger positions.

FIG. 1 is a side view with parts cutaway and removed of a vehicleshowing the passenger compartment containing a rear facing child seat onthe front passenger seat and a preferred mounting location for anoccupant and rear facing child seat presence detector including anantenna field sensor and a resonator or reflector placed onto theforward most portion of the child seat.

FIG. 2 is a side view with parts cutaway and removed showingschematically the interface between the vehicle interior monitoringsystem of at least one of the inventions disclosed herein and thevehicle cellular or other telematics communication system including anantenna field sensor.

FIG. 3 is a side view with parts cutaway and removed of a vehicleshowing the passenger compartment containing a box on the frontpassenger seat and a preferred mounting location for an occupant andrear facing child seat presence detector and including an antenna fieldsensor.

FIG. 4 is a side view with parts cutaway and removed of a vehicleshowing the passenger compartment containing a driver and a preferredmounting location for an occupant identification system and including anantenna field sensor and an inattentiveness response button.

FIG. 5 is a side view, with certain portions removed or cut away, of aportion of the passenger compartment of a vehicle showing severalpreferred mounting locations of occupant position sensors for sensingthe position of the vehicle driver.

FIG. 6 shows a seated-state detecting unit in accordance with thepresent invention and the connections between ultrasonic orelectromagnetic sensors, a weight sensor, a reclining angle detectingsensor, a seat track position detecting sensor, a heartbeat sensor, amotion sensor, a neural network, and an airbag system installed within avehicular compartment.

FIG. 7 is a perspective view of a vehicle showing the position of theultrasonic or electromagnetic sensors relative to the driver and frontpassenger seats.

FIG. 8A is a side planar view, with certain portions removed or cutaway, of a portion of the passenger compartment of a vehicle showingseveral preferred mounting locations of interior vehicle monitoringsensors shown particularly for sensing the vehicle driver illustratingthe wave pattern from a CCD or CMOS optical position sensor mountedalong the side of the driver or centered above his or her head.

FIG. 8B is a view as in FIG. 8A illustrating the wave pattern from anoptical system using an infrared light source and a CCD or CMOS arrayreceiver using the windshield as a reflection surface and showingschematically the interface between the vehicle interior monitoringsystem of at least one of the inventions disclosed herein and aninstrument panel mounted inattentiveness warning light or buzzer andreset button.

FIG. 8C is a view as in FIG. 8A illustrating the wave pattern from anoptical system using an infrared light source and a CCD or CMOS arrayreceiver where the CCD or CMOS array receiver is covered by a lenspermitting a wide angle view of the contents of the passengercompartment.

FIG. 8D is a view as in FIG. 8A illustrating the wave pattern from apair of small CCD or CMOS array receivers and one infrared transmitterwhere the spacing of the CCD or CMOS arrays permits an accuratemeasurement of the distance to features on the occupant.

FIG. 8E is a view as in FIG. 8A illustrating the wave pattern from a setof ultrasonic transmitter/receivers where the spacing of the transducersand the phase of the signal permits an accurate focusing of theultrasonic beam and thus the accurate measurement of a particular pointon the surface of the driver.

FIG. 9 is a circuit diagram of the seated-state detecting unit of thepresent invention.

FIGS. 10( a), 10(b) and 10(c) are each a diagram showing theconfiguration of the reflected waves of an ultrasonic wave transmittedfrom each transmitter of the ultrasonic sensors toward the passengerseat, obtained within the time that the reflected wave arrives at areceiver, FIG. 10( a) showing an example of the reflected waves obtainedwhen a passenger is in a normal seated-state, FIG. 10( b) showing anexample of the reflected waves obtained when a passenger is in anabnormal seated-state (where the passenger is seated too close to theinstrument panel), and FIG. 10( c) showing a transmit pulse.

FIGS. 11A and 11B are functional block diagrams of the ultrasonicimaging system illustrated in FIG. 1 using a microprocessor, DSP orfield programmable gate array (FGPA) (FIG. 11A) or an applicationspecific integrated circuit (ASIC) (FIG. 11B).

FIG. 12 is a circuit schematic illustrating the use of the occupantposition sensor in conjunction with the remainder of the inflatablerestraint system.

FIG. 13 is a schematic illustrating the circuit of an occupantposition-sensing device using a modulated infrared signal, beatfrequency and phase detector system.

FIG. 14 is a flowchart showing the training steps of a neural network.

FIG. 15A is an explanatory diagram of a process for normalizing thereflected wave and shows normalized reflected waves.

FIG. 15B is a diagram similar to FIG. 15A showing a step of extractingdata based on the normalized reflected waves and a step of weighting theextracted data by employing the data of the seat track positiondetecting sensor, the data of the reclining angle detecting sensor, andthe data of the weight sensor.

FIG. 16 is a perspective view of the interior of the passengercompartment of an automobile, with parts cut away and removed, showing avariety of transmitters that can be used in a phased array system.

FIG. 17 is a perspective view of a vehicle containing an adult occupantand an occupied infant seat on the front seat with the vehicle shown inphantom illustrating one preferred location of the transducers placedaccording to the methods taught in at least one of the inventionsdisclosed herein.

FIG. 18 is a schematic illustration of a system for controllingoperation of a vehicle or a component thereof based on recognition of anauthorized individual.

FIG. 19 is a schematic illustration of a method for controllingoperation of a vehicle based on recognition of an individual.

FIG. 20 is a schematic illustration of the environment monitoring inaccordance with the invention.

FIG. 21 is a diagram showing an example of an occupant sensing strategyfor a single camera optical system.

FIG. 22 is a processing block diagram of the example of FIG. 21.

FIG. 23 is a block diagram of an antenna-based near field objectdiscriminator.

FIG. 24 is a side view, with certain portions removed or cut away, of aportion of the passenger compartment of a vehicle showing preferredmounting locations of optical interior vehicle monitoring sensors

FIG. 25 is a side view with parts cutaway and removed of a subjectvehicle and an oncoming vehicle, showing the headlights of the oncomingvehicle and the passenger compartment of the subject vehicle, containingdetectors of the driver's eyes and detectors for the headlights of theoncoming vehicle and the selective filtering of the light of theapproaching vehicle's headlights through the use of electro-chromicglass, organic or metallic semiconductor polymers or electrophericparticulates (SPD) in the windshield.

FIG. 25A is an enlarged view of the section 25A in FIG. 25.

FIG. 26 is a side view with parts cutaway and removed of a vehicle and afollowing vehicle showing the headlights of the following vehicle andthe passenger compartment of the leading vehicle containing a driver anda preferred mounting location for driver eyes and following vehicleheadlight detectors and the selective filtering of the light of thefollowing vehicle's headlights through the use of electrochromic glass,SPD glass or equivalent, in the rear view mirror.

FIG. 26A is an enlarged view of the section designated 26A in FIG. 26.

FIG. 26B is an enlarged view of the section designated 26B in FIG. 26A.

FIG. 27 illustrates the interior of a passenger compartment with a rearview mirror, a camera for viewing the eyes of the driver and a largegenerally transparent visor for glare filtering.

FIG. 28 is a perspective view of an automatic seat adjustment system,with the seat shown in phantom, with a movable headrest and sensors formeasuring the height of the occupant from the vehicle seat showingmotors for moving the seat and a control circuit connected to thesensors and motors.

FIG. 29 is a view of the seat of FIG. 28 showing a system for changingthe stiffness and the damping of the seat.

FIG. 30 is a flow chart of the environment monitoring in accordance withthe invention.

FIG. 31 is a schematic drawing of one embodiment of an occupantrestraint device control system in accordance with the invention.

FIG. 32 is a flow chart of the operation of one embodiment of anoccupant restraint device control method in accordance with theinvention.

FIG. 33 is a view showing an inflated airbag and an arrangement forcontrolling both the flow of gas into and the flow of gas out of theairbag during the crash where the determination is made based on aheight sensor located in the headrest and a weight sensor in the seat.

FIG. 33A illustrates the valving system of FIG. 33.

FIG. 34 is a side plan view of the interior of an automobile, withportions cut away and removed, with two occupant height measuringsensors, one mounted into the headliner above the occupant's head andthe other mounted onto the A-pillar and also showing a seatbeltassociated with the seat wherein the seatbelt has an adjustable upperanchorage point which is automatically adjusted based on the height ofthe occupant.

FIG. 35 is a view of the seat of FIG. 28 showing motors for changing thetilt of seat back and the lumbar support.

FIG. 36 is a view as in FIG. 34 showing a driver and driver seat with anautomatically adjustable steering column and pedal system which isadjusted based on the morphology of the driver.

FIG. 37 is a view similar to FIG. 28 showing the occupant's eyes and theseat adjusted to place the eyes at a particular vertical position forproper viewing through the windshield and rear view mirror.

FIG. 38 is a side view with parts cutaway and removed of a vehicleshowing the passenger compartment containing a driver and a preferredmounting location for an occupant position sensor for use in sideimpacts and also of a rear of occupant's head locator for use with aheadrest adjustment system to reduce whiplash injuries in rear impactcrashes.

DETAILED DESCRIPTION OF THE INVENTION

A patent or literature referred to below is incorporated by reference inits entirety. Also, although many of the examples below relate to aparticular vehicle, an automobile, the invention is not limited to anyparticular vehicle and is thus applicable to all relevant vehiclesincluding shipping containers and truck trailers and to all compartmentsof a vehicle including, for example, the passenger compartment and thetrunk of an automobile or truck.

1. General Occupant Sensors

Referring to the accompanying drawings, FIG. 1 is a side view, withparts cutaway and removed of a vehicle showing the passengercompartment, or passenger container, containing a rear facing child seat2 on a front passenger seat 4 and a preferred mounting location for afirst embodiment of a vehicle interior monitoring system in accordancewith the invention. The interior monitoring system is capable ofdetecting the presence of an object, occupying objects such as a box, anoccupant or a rear facing child seat 2, determining the type of object,determining the location of the object, and/or determining anotherproperty or characteristic of the object. A property of the object couldbe the orientation of a child seat, the velocity of an adult and thelike. For example, the vehicle interior monitoring system can determinethat an object is present on the seat, that the object is a child seatand that the child seat is rear-facing. The vehicle interior monitoringsystem could also determine that the object is an adult, that he isdrunk and that he is out of position relative to the airbag.

In this embodiment, three transducers 6, 8 and 10 are used alone, or,alternately in combination with one or more antenna near fieldmonitoring sensors or transducers, 12, 14 and 16, although any number ofwave-transmitting transducers or radiation-receiving receivers may beused. Such transducers or receivers may be of the type that emit orreceive a continuous signal, a time varying signal or a spatial varyingsignal such as in a scanning system and each may comprise only atransmitter which transmits energy, waves or radiation, only a receiverwhich receives energy, waves or radiation, both a transmitter and areceiver capable of transmitting and receiving energy, waves orradiation, an electric field sensor, a capacitive sensor, or aself-tuning antenna-based sensor, weight sensor, chemical sensor, motionsensor or vibration sensor, for example.

One particular type of radiation-receiving receiver for use in theinvention receives electromagnetic waves and another receives ultrasonicwaves.

In an ultrasonic embodiment, transducer 8 can be used as a transmitterand transducers 6 and 10 can be used as receivers. Other combinationscan be used such as where all transducers are transceivers (transmittersand receivers). For example, transducer 8 can be constructed to transmitultrasonic energy toward the front passenger seat, which is modified, inthis case by the occupying item of the passenger seat, i.e., the rearfacing child seat 2, and the modified waves are received by thetransducers 6 and 10, for example. A more common arrangement is wheretransducers 6, 8 and 10 are all transceivers. Modification of theultrasonic energy may constitute reflection of the ultrasonic energy asthe ultrasonic energy is reflected back by the occupying item of theseat. The waves received by transducers 6 and 10 vary with timedepending on the shape of the object occupying the passenger seat, inthis case the rear facing child seat 2. Each different occupying itemwill reflect back waves having a different pattern. Also, the pattern ofwaves received by transducer 6 will differ from the pattern received bytransducer 10 in view of its different mounting location. Thisdifference generally permits the determination of location of thereflecting surface (i.e., the rear facing child seat 2) throughtriangulation. Through the use of two transducers 6, 10, a sort ofstereographic image is received by the two transducers and recorded foranalysis by processor 20, which is coupled to the transducers 6, 8, 10,e.g., by wires or wirelessly. This image will differ for each objectthat is placed on the vehicle seat and it will also change for eachposition of a particular object and for each position of the vehicleseat. Elements 6, 8, 10, although described as transducers, arerepresentative of any type of component used in a wave-based analysistechnique. Also, although the example of an automobile passengercompartment has been shown, the same principle can be used formonitoring the interior of any vehicle including in particular shippingcontainers and truck trailers.

The positioning of the transducers 6, 10 to obtain a stereoscopic imagemay be achieved in a number of different ways. For example, eachtransducer 6, 10 may be arranged on perpendicular sides of a virtualrectangle so that one transducer 6 obtains images encompassing twodimensions while the other transducer 10 obtains images encompassing twodimensions which are not the same as the two dimensions encompassed byimages obtained by transducer 6.

Wave-type sensors as the transducers 6, 8, 10 as well as electric fieldsensors 12, 14, 16 are mentioned above. Electric field sensors and wavesensors are essentially the same from the point of view of sensing thepresence of an occupant in a vehicle. In both cases, a time varyingelectric field is disturbed or modified by the presence of the occupant.At high frequencies in the visual, infrared and high frequency radiowave region, the sensor is based on its capability to sense a change ofwave characteristics of the electromagnetic field, such as amplitude,phase or frequency. As the frequency drops, other characteristics of thefield are measured. At still lower frequencies, the occupant'sdielectric properties modify parameters of the reactive electric fieldin the occupied space between or near the plates of a capacitor. In thislatter case, the sensor senses the change in charge distribution on thecapacitor plates by measuring, for example, the current wave magnitudeor phase in the electric circuit that drives the capacitor. Thesemeasured parameters are directly connected with parameters of thedisplacement current in the occupied space. In all cases, the presenceof the occupant reflects, absorbs or modifies the waves or variations inthe electric field in the space occupied by the occupant. Thus, for thepurposes of at least one of the inventions disclosed herein,capacitance, electric field or electromagnetic wave sensors areequivalent and although they are all technically “field” sensors theywill be considered as “wave” sensors herein. What follows is adiscussion comparing the similarities and differences between two typesof field or wave sensors, electromagnetic wave sensors and capacitivesensors as exemplified by Kithil in U.S. Pat. No. 5,702,634.

An electromagnetic field disturbed or emitted by a passenger in the caseof an electromagnetic wave sensor, for example, and the electric fieldsensor of Kithil, for example, are in many ways similar and equivalentfor the purposes of at least one of the inventions disclosed herein. Theelectromagnetic wave sensor is an actual electromagnetic wave sensor bydefinition because they sense parameters of an electromagnetic wave,which is a coupled pair of continuously changing electric and magneticfields. The electric field here is not a static, potential one. It isessentially a dynamic, rotational electric field coupled with a changingmagnetic one, that is, an electromagnetic wave. It cannot be produced bya steady distribution of electric charges. It is initially produced bymoving electric charges in a transmitter, even if this transmitter is apassenger body for the case of a passive infrared sensor.

In the Kithil sensor, a static electric field is declared as an initialmaterial agent coupling a passenger and a sensor (see Column 5, lines5-7: “The proximity sensor 12 each function by creating an electrostaticfield between oscillator input loop 54 and detector output loop 56,which is affected by presence of a person near by, as a result ofcapacitive coupling, . . . ”). It is a potential, non-rotationalelectric field. It is not necessarily coupled with any magnetic field.It is the electric field of a capacitor. It can be produced with asteady distribution of electric charges. Thus, it is not anelectromagnetic wave by definition but if the sensor is driven by avarying current, then it produces a quasistatic electric field in thespace between/near the plates of the capacitor.

Kithil declares that his capacitance sensor uses a static electricfield. Thus, from the consideration above, one can conclude thatKithil's sensor cannot be treated as a wave sensor because there are noactual electromagnetic waves but only a static electric field of thecapacitor in the sensor system. However, this is not believed to be thecase. The Kithil system could not operate with a true static electricfield because a steady system does not carry any information. Therefore,Kithil is forced to use an oscillator, causing an alternate current inthe capacitor and a reactive quasi-static electric field in the spacebetween the capacitor plates, and a detector to reveal an informativechange of the sensor capacitance caused by the presence of an occupant(see FIG. 7 and its description). In this case, the system becomes a“wave sensor” in the sense that it starts generating an actualtime-varying electric field that certainly originates electromagneticwaves according to the definition above. That is, Kithil's sensor can betreated as a wave sensor regardless of the shape of the electric fieldthat it creates, a beam or a spread shape.

As follows from the Kithil patent, the capacitor sensor is likely aparametric system where the capacitance of the sensor is controlled bythe influence of the passenger body. This influence is transferred bymeans of the near electromagnetic field (i.e., the wave-like process)coupling the capacitor electrodes and the body. It is important to notethat the same influence takes place with a real static electric fieldalso, that is in absence of any wave phenomenon. This would be asituation if there were no oscillator in Kithil's system. However, sucha system is not workable and thus Kithil reverts to a dynamic systemusing time-varying electric fields.

Thus, although Kithil declares that the coupling is due to a staticelectric field, such a situation is not realized in his system becausean alternating electromagnetic field (“quasi-wave”) exists in the systemdue to the oscillator. Thus, his sensor is actually a wave sensor, thatis, it is sensitive to a change of a wave field in the vehicularcompartment. This change is measured by measuring the change of itscapacitance. The capacitance of the sensor system is determined by theconfiguration of its electrodes, one of which is a human body, that is,the passenger inside of and the part which controls the electrodeconfiguration and hence a sensor parameter, the capacitance.

The physics definition of “wave” from Webster's Encyclopedic UnabridgedDictionary is: “11. Physics. A progressive disturbance propagated frompoint to point in a medium or space without progress or advance of thepoints themselves, . . . ”. In a capacitor, the time that it takes forthe disturbance (a change in voltage) to propagate through space, thedielectric and to the opposite plate is generally small and neglectedbut it is not zero. As the frequency driving the capacitor increases andthe distance separating the plates increases, this transmission time asa percentage of the period of oscillation can become significant.Nevertheless, an observer between the plates will see the rise and fallof the electric field much like a person standing in the water of anocean. The presence of a dielectric body between the plates causes thewaves to get bigger as more electrons flow to and from the plates of thecapacitor. Thus, an occupant affects the magnitude of these waves whichis sensed by the capacitor circuit. Thus, the electromagnetic field is amaterial agent that carries information about a passenger's position inboth Kithil's and a beam-type electromagnetic wave sensor.

For ultrasonic systems, the “image” recorded from each ultrasonictransducer/receiver, is actually a time series of digitized data of theamplitude of the received signal versus time. Since there are tworeceivers, two time series are obtained which are processed by theprocessor 20. The processor 20 may include electronic circuitry andassociated, embedded software. Processor 20 constitutes one form ofgenerating means in accordance with the invention which generatesinformation about the occupancy of the passenger compartment based onthe waves received by the transducers 6, 8, 10.

When different objects are placed on the front passenger seat, theimages from transducers 6, 8, 10 for example, are different but thereare also similarities between all images of rear facing child seats, forexample, regardless of where on the vehicle seat it is placed andregardless of what company manufactured the child seat. Alternately,there will be similarities between all images of people sitting on theseat regardless of what they are wearing, their age or size. The problemis to find the “rules” which differentiate the images of one type ofobject from the images of other types of objects, e.g., whichdifferentiate the occupant images from the rear facing child seatimages. The similarities of these images for various child seats arefrequently not obvious to a person looking at plots of the time seriesand thus computer algorithms are developed to sort out the variouspatterns. For a more detailed discussion of pattern recognition see U.S.Pat. No. RE 37,260.

The determination of these rules is important to the pattern recognitiontechniques used in at least one of the inventions disclosed herein. Ingeneral, three approaches have been useful, artificial intelligence,fuzzy logic and artificial neural networks (including cellular andmodular or combination neural networks and support vectormachines—although additional types of pattern recognition techniques mayalso be used, such as sensor fusion). In some implementations of atleast one of the inventions disclosed herein, such as the determinationthat there is an object in the path of a closing window as describedbelow, the rules are sufficiently obvious that a trained researcher cansometimes look at the returned signals and devise a simple algorithm tomake the required determinations. In others, such as the determinationof the presence of a rear facing child seat or of an occupant,artificial neural networks can be used to determine the rules. One suchset of neural network software for determining the pattern recognitionrules is available from the International Scientific Research, Inc. ofPanama City, Panama.

Electromagnetic energy based occupant sensors exist that use manyportions of the electromagnetic spectrum. A system based on theultraviolet, visible or infrared portions of the spectrum generallyoperate with a transmitter and a receiver of reflected radiation. Thereceiver may be a camera or a photo detector such as a pin or avalanchediode as described in above-referenced patents and patent applications.At other frequencies, the absorption of the electromagnetic energy isprimarily used and at still other frequencies the capacitance orelectric field influencing effects are used. Generally, the human bodywill reflect, scatter, absorb or transmit electromagnetic energy invarious degrees depending on the frequency of the electromagnetic waves.All such occupant sensors are included herein.

In an embodiment wherein electromagnetic energy is used, it is to beappreciated that any portion of the electromagnetic signals thatimpinges upon, surrounds or involves a body portion of the occupant isat least partially absorbed by the body portion. Sometimes, this is dueto the fact that the human body is composed primarily of water, and thatelectromagnetic energy of certain frequencies is readily absorbed bywater. The amount of electromagnetic signal absorption is related to thefrequency of the signal, and size or bulk of the body portion that thesignal impinges upon. For example, a torso of a human body tends toabsorb a greater percentage of electromagnetic energy than a hand of ahuman body.

Thus, when electromagnetic waves or energy signals are transmitted by atransmitter, the returning waves received by a receiver provide anindication of the absorption of the electromagnetic energy. That is,absorption of electromagnetic energy will vary depending on the presenceor absence of a human occupant, the occupant's size, bulk, surfacereflectivity, etc. depending on the frequency, so that different signalswill be received relating to the degree or extent of absorption by theoccupying item on the seat. The receiver will produce a signalrepresentative of the returned waves or energy signals which will thusconstitute an absorption signal as it corresponds to the absorption ofelectromagnetic energy by the occupying item in the seat.

One or more of the transducers 6, 8, 10 can also be image-receivingdevices, such as cameras, which take images of the interior of thepassenger compartment. These images can be transmitted to a remotefacility to monitor the passenger compartment or can be stored in amemory device for use in the event of an accident, i.e., to determinethe status of the occupant(s) of the vehicle prior to the accident. Inthis manner, it can be ascertained whether the driver was fallingasleep, talking on the phone, etc.

A memory device for storing images of the passenger compartment, andalso for receiving and storing any other information, parameters andvariables relating to the vehicle or occupancy of the vehicle, may be inthe form of a standardized “black box” (instead of or in addition to amemory part in a processor 20). The IEEE Standards Association iscurrently beginning to develop an international standard for motorvehicle event data recorders. The information stored in the black boxand/or memory unit in the processor 20, can include the images of theinterior of the passenger compartment as well as the number of occupantsand the health state of the occupant(s). The black box would preferablybe tamper-proof and crash-proof and enable retrieval of the informationafter a crash.

Transducer 8 can also be a source of electromagnetic radiation, such asan LED, and transducers 6 and 10 can be CMOS, CCD imagers or otherdevices sensitive to electromagnetic radiation or fields. This “image”or return signal will differ for each object that is placed on thevehicle seat, or elsewhere in the vehicle, and it will also change foreach position of a particular object and for each position of thevehicle seat or other movable objects within the vehicle. Elements 6, 8,10, although described as transducers, are representative of any type ofcomponent used in a wave-based or electric field analysis technique,including, e.g., a transmitter, receiver, antenna or a capacitor plate.

Transducers 12, 14 and 16 can be antennas placed in the seat andinstrument panel, or other convenient location within the vehicle, suchthat the presence of an object, particularly a water-containing objectsuch as a human, disturbs the near field of the antenna. Thisdisturbance can be detected by various means such as with Micrel partsMICREF102 and MICREF104, which have a built-in antenna auto-tunecircuit. Note, these parts cannot be used as is and it is necessary toredesign the chips to allow the auto-tune information to be retrievedfrom the chip.

Other types of transducers can be used along with the transducers 6, 8,10 or separately and all are contemplated by at least one of theinventions disclosed herein. Such transducers include other wave devicessuch as radar or electronic field sensing systems such as described inU.S. Pat. No. 5,366,241, U.S. Pat. No. 5,602,734, U.S. Pat. No.5,691,693, U.S. Pat. No. 5,802,479, U.S. Pat. No. 5,844,486, U.S. Pat.No. 6,014,602, U.S. Pat. No. 6,275,146 and U.S. Pat. No. 5,948,031.Another technology, for example, uses the fact that the content of thenear field of an antenna affects the resonant tuning of the antenna.Examples of such a device are shown as antennas 12, 14 and 16 in FIG. 1.By going to lower frequencies, the near field range is increased andalso at such lower frequencies, a ferrite-type antenna could be used tominimize the size of the antenna. Other antennas that may be applicablefor a particular implementation include dipole, microstrip, patch, Yagietc. The frequency transmitted by the antenna can be swept and the(VSWR) voltage and current in the antenna feed circuit can be measured.Classification by frequency domain is then possible. That is, if thecircuit is tuned by the antenna, the frequency can be measured todetermine the object in the field.

An alternate system is shown in FIG. 2, which is a side view showingschematically the interface between the vehicle interior monitoringsystem of at least one of the inventions disclosed herein and thevehicle cellular or other communication system 32, such as a satellitebased system such as that supplied by Skybitz, having an associatedantenna 34. In this view, an adult occupant 30 is shown sitting on thefront passenger seat 4 and two transducers 6 and 8 are used to determinethe presence (or absence) of the occupant on that seat 4. One of thetransducers 8 in this case acts as both a transmitter and receiver whilethe other transducer 6 acts only as a receiver. Alternately, transducer6 could serve as both a transmitter and receiver or the transmittingfunction could be alternated between the two devices. Also, in manycases, more than two transmitters and receivers are used and in stillother cases, other types of sensors, such as weight, chemical,radiation, vibration, acoustic, seatbelt tension sensor or switch,heartbeat, self tuning antennas (12, 14), motion and seat and seatbackposition sensors, are also used alone or in combination with thetransducers 6 and 8. As is also the case in FIG. 1, the transducers 6and 8 are attached to the vehicle embedded in the A-pillar and headlinertrim, where their presence is disguised, and are connected to processor20 that may also be hidden in the trim as shown or elsewhere. Othermounting locations can also be used as disclosed in U.S. Pat. No. RE37,260.

The transducers 6 and 8 in conjunction with the pattern recognitionhardware and software described below enable the determination of thepresence of an occupant within a short time after the vehicle isstarted. The software is implemented in processor 20 and is packaged ona printed circuit board or flex circuit along with the transducers 6 and8. Similar systems can be located to monitor the remaining seats in thevehicle, also determine the presence of occupants at the other seatinglocations and this result is stored in the computer memory, which ispart of each monitoring system processor 20. Processor 20 thus enables acount of the number of occupants in the vehicle to be obtained byaddition of the determined presence of occupants by the transducersassociated with each seating location, and in fact, can be designed toperform such an addition, the principles illustrated for automobilevehicles are applicable by those skilled in the art to other vehiclessuch as shipping containers or truck trailers and to other compartmentsof an automotive vehicle such as the vehicle trunk.

For a general object, transducers 6, 8, 9, 10 can also be used todetermine the type of object, determine the location of the object,and/or determine another property or characteristic of the object. Aproperty of the object could be the orientation of a child seat, thevelocity of an adult and the like. For example, the transducers 6, 8, 9,10 can be designed to enable a determination that an object is presenton the seat, that the object is a child seat and that the child seat isrear-facing.

The transducers 6 and 8 are attached to the vehicle buried in the trimsuch as the A-pillar trim, where their presence can be disguised, andare connected to processor 20 that may also be hidden in the trim asshown (this being a non-limiting position for the processor 20). TheA-pillar is the roof support pillar that is closest to the front of thevehicle and which, in addition to supporting the roof, also supports thefront windshield and the front door. Other mounting locations can alsobe used. For example, transducers 6, 8 can be mounted inside the seat(along with or in place of transducers 12 and 14), in the ceiling of thevehicle, in the B-pillar, in the C-pillar and in the doors. Indeed, thevehicle interior monitoring system in accordance with the invention maycomprise a plurality of monitoring units, each arranged to monitor aparticular seating location. In this case, for the rear seatinglocations, transducers might be mounted in the B-pillar or C-pillar orin the rear of the front seat or in the rear side doors. Possiblemounting locations for transducers, transmitters, receivers and otheroccupant sensing devices are disclosed in above-referenced patentapplications and all of these mounting locations are contemplated foruse with the transducers described herein.

The cellular phone or other communications system 32 outputs to anantenna 34. The transducers 6, 8, 12 and 14 in conjunction with thepattern recognition hardware and software, which is implemented inprocessor 20 and is packaged on a printed circuit board or flex circuitalong with the transducers 6 and 8, determine the presence of anoccupant within a few seconds after the vehicle is started, or within afew seconds after the door is closed. Similar systems located to monitorthe remaining seats in the vehicle, also determine the presence ofoccupants at the other seating locations and this result is stored inthe computer memory which is part of each monitoring system processor20.

Periodically and in particular in the event of an accident, theelectronic system associated with the cellular phone system 32interrogates the various interior monitoring system memories and arrivesat a count of the number of occupants in the vehicle, and optionally,even makes a determination as to whether each occupant was wearing aseatbelt and if he or she is moving after the accident. The phone orother communications system then automatically dials the EMS operator(such as 911 or through a telematics service such as OnStar®) and theinformation obtained from the interior monitoring systems is forwardedso that a determination can be made as to the number of ambulances andother equipment to send to the accident site, for example. Such vehicleswill also have a system, such as the global positioning system, whichpermits the vehicle to determine its exact location and to forward thisinformation to the EMS operator. Other systems can be implemented inconjunction with the communication with the emergency services operator.For example, a microphone and speaker can be activated to permit theoperator to attempt to communicate with the vehicle occupant(s) andthereby learn directly of the status and seriousness of the condition ofthe occupant(s) after the accident.

Thus, in basic embodiments of the invention, wave or otherenergy-receiving transducers are arranged in the vehicle at appropriatelocations, trained if necessary depending on the particular embodiment,and function to determine whether a life form is present in the vehicleand if so, how many life forms are present and where they are locatedetc. To this end, transducers can be arranged to be operative at only asingle seating location or at multiple seating locations with aprovision being made to eliminate a repetitive count of occupants. Adetermination can also be made using the transducers as to whether thelife forms are humans, or more specifically, adults, child in childseats, etc. As noted herein, this is possible using pattern recognitiontechniques. Moreover, the processor or processors associated with thetransducers can be trained to determine the location of the life forms,either periodically or continuously or possibly only immediately before,during and after a crash. The location of the life forms can be asgeneral or as specific as necessary depending on the systemrequirements, i.e., a determination can be made that a human is situatedon the driver's seat in a normal position (general) or a determinationcan be made that a human is situated on the driver's seat and is leaningforward and/or to the side at a specific angle as well as the positionof his or her extremities and head and chest (specifically). The degreeof detail is limited by several factors, including, for example, thenumber and position of transducers and training of the patternrecognition algorithm(s).

In addition to the use of transducers to determine the presence andlocation of occupants in a vehicle, other sensors could also be used.For example, a heartbeat sensor which determines the number and presenceof heartbeat signals can also be arranged in the vehicle, which wouldthus also determine the number of occupants as the number of occupantswould be equal to the number of heartbeat signals detected. Conventionalheartbeat sensors can be adapted to differentiate between a heartbeat ofan adult, a heartbeat of a child and a heartbeat of an animal. As itsname implies, a heartbeat sensor detects a heartbeat, and the magnitudeand/or frequency thereof, of a human occupant of the seat, if such ahuman occupant is present. The output of the heartbeat sensor is inputto the processor of the interior monitoring system. One heartbeat sensorfor use in the invention may be of the types as disclosed in McEwan(U.S. Pat. Nos. 5,573,012 and 5,766,208). The heartbeat sensor can bepositioned at any convenient position relative to the seats whereoccupancy is being monitored. A preferred location is within the vehicleseatback.

An alternative way to determine the number of occupants is to monitorthe weight being applied to the seats, i.e., each seating location, byarranging weight sensors at each seating location which might also beable to provide a weight distribution of an object on the seat. Analysisof the weight and/or weight distribution by a predetermined method canprovide an indication of occupancy by a human, an adult or child, or aninanimate object.

Another type of sensor which is not believed to have been used in aninterior monitoring system previously is a micropower impulse radar(MIR) sensor which determines motion of an occupant and thus candetermine his or her heartbeat (as evidenced by motion of the chest).Such an MIR sensor can be arranged to detect motion in a particular areain which the occupant's chest would most likely be situated or could becoupled to an arrangement which determines the location of theoccupant's chest and then adjusts the operational field of the MIRsensor based on the determined location of the occupant's chest. Amotion sensor utilizing a micro-power impulse radar (MIR) system asdisclosed, for example, in McEwan (U.S. Pat. No. 5,361,070), as well asmany other patents by the same inventor.

Motion sensing is accomplished by monitoring a particular range from thesensor as disclosed in that patent. MIR is one form of radar which hasapplicability to occupant sensing and can be mounted at variouslocations in the vehicle. It has an advantage over ultrasonic sensors inthat data can be acquired at a higher speed and thus the motion of anoccupant can be more easily tracked. The ability to obtain returns overthe entire occupancy range is somewhat more difficult than withultrasound resulting in a more expensive system overall. MIR hasadditional advantages in lack of sensitivity to temperature variationand has a comparable resolution to about 40 kHz ultrasound. Resolutioncomparable to higher frequency ultrasound is also possible.Additionally, multiple MIR sensors can be used when high speed trackingof the motion of an occupant during a crash is required since they canbe individually pulsed without interfering with each through timedivision multiplexing.

An alternative way to determine motion of the occupant(s) is to monitorthe weight distribution of the occupant whereby changes in weightdistribution after an accident would be highly suggestive of movement ofthe occupant. A system for determining the weight distribution of theoccupants could be integrated or otherwise arranged in the seats such asthe front seat 4 of the vehicle and several patents and publicationsdescribe such systems.

More generally, any sensor which determines the presence and healthstate of an occupant can also be integrated into the vehicle interiormonitoring system in accordance with the invention. For example, asensitive motion sensor can determine whether an occupant is breathingand a chemical sensor can determine the amount of carbon dioxide, or theconcentration of carbon dioxide, in the air in the passenger compartmentof the vehicle which can be correlated to the health state of theoccupant(s). The motion sensor and chemical sensor can be designed tohave a fixed operational field situated where the occupant's mouth ismost likely to be located. In this manner, detection of carbon dioxidein the fixed operational field could be used as an indication of thepresence of a human occupant in order to enable the determination of thenumber of occupants in the vehicle. In the alternative, the motionsensor and chemical sensor can be adjustable and adapted to adjust theiroperational field in conjunction with a determination by an occupantposition and location sensor which would determine the location ofspecific parts of the occupant's body, e.g., his or her chest or mouth.Furthermore, an occupant position and location sensor can be used todetermine the location of the occupant's eyes and determine whether theoccupant is conscious, i.e., whether his or her eyes are open or closedor moving.

The use of chemical sensors can also be used to detect whether there isblood present in the vehicle, for example, after an accident.Additionally, microphones can detect whether there is noise in thevehicle caused by groaning, yelling, etc., and transmit any such noisethrough the cellular or other communication connection to a remotelistening facility (such as operated by OnStar®).

In FIG. 3, a view of the system of FIG. 1 is illustrated with a box 28shown on the front passenger seat in place of a rear facing child seat.The vehicle interior monitoring system is trained to recognize that thisbox 28 is neither a rear facing child seat nor an occupant and thereforeit is treated as an empty seat and the deployment of the airbag or otheroccupant restraint device is suppressed. For other vehicles, it may bethat just the presence of a box or its motion or chemical or radiationeffluents that are desired to be monitored. The auto-tune antenna-basedsystem 12, 14 is particularly adept at making this distinctionparticularly if the box 28 does not contain substantial amounts ofwater. Although a simple implementation of the auto-tune antenna systemis illustrated, it is of course possible to use multiple antennaslocated in the seat 4 and elsewhere in the passenger compartment andthese antenna systems can either operate at one or a multiple ofdifferent frequencies to discriminate type, location and/or relativesize of the object being investigated. This training can be accomplishedusing a neural network or modular neural network with the commerciallyavailable software. The system assesses the probability that the box 28is a person, however, and if there is even the remotest chance that itis a person, the airbag deployment is not suppressed. The system is thustypically biased toward enabling airbag deployment.

In cases where different levels of airbag inflation are possible, andthere are different levels of injury associated with an out of positionoccupant being subjected to varying levels of airbag deployment, it issometimes possible to permit a depowered or low level airbag deploymentin cases of uncertainty. If, for example, the neural network has aproblem distinguishing whether a box or a forward facing child seat ispresent on the vehicle seat, the decision can be made to deploy theairbag in a depowered or low level deployment state. Other situationswhere such a decision could be made would be when there is confusion asto whether a forward facing human is in position or out-of-position.

Neural networks systems frequently have problems in accuratelydiscriminating the exact location of an occupant especially whendifferent-sized occupants are considered. This results in a gray zonearound the border of the keep out zone where the system provides a weakfire or weak no fire decision. For those cases, deployment of the airbagin a depowered state can resolve the situation since an occupant in agray zone around the keep out zone boundary would be unlikely to beinjured by such a depowered deployment while significant airbagprotection is still being supplied.

Electromagnetic or ultrasonic energy can be transmitted in three modesin determining the position of an occupant, for example. In most of thecases disclosed above, it is assumed that the energy will be transmittedin a broad diverging beam which interacts with a substantial portion ofthe occupant or other object to be monitored. This method can have thedisadvantage that it will reflect first off the nearest object and,especially if that object is close to the transmitter, it may mask thetrue position of the occupant or object. It can also reflect off manyparts of the object where the reflections can be separated in time andprocessed as in an ultrasonic occupant sensing system. This can also bepartially overcome through the use of the second mode which uses anarrow beam. In this case, several narrow beams are used. These beamsare aimed in different directions toward the occupant from a positionsufficiently away from the occupant or object such that interference isunlikely.

A single receptor could be used provided the beams are either cycled onat different times or are of different frequencies. Another approach isto use a single beam emanating from a location which has an unimpededview of the occupant or object such as the windshield header in the caseof an automobile or near the roof at one end of a trailer or shippingcontainer, for example. If two spaced apart CCD array receivers areused, the angle of the reflected beam can be determined and the locationof the occupant can be calculated. The third mode is to use a singlebeam in a manner so that it scans back and forth and/or up and down, orin some other pattern, across the occupant, object or the space ingeneral. In this manner, an image of the occupant or object can beobtained using a single receptor and pattern recognition software can beused to locate the head or chest of the occupant or size of the object,for example. The beam approach is most applicable to electromagneticenergy but high frequency ultrasound can also be formed into a narrowbeam.

A similar effect to modifying the wave transmission mode can also beobtained by varying the characteristics of the receptors. Throughappropriate lenses or reflectors, receptors can be made to be mostsensitive to radiation emitted from a particular direction. In thismanner, a single broad beam transmitter can be used coupled with anarray of focused receivers, or a scanning receiver, to obtain a roughimage of the occupant or occupying object.

Each of these methods of transmission or reception could be used, forexample, at any of the preferred mounting locations shown in FIG. 5.

As shown in FIG. 7, there are provided four sets of wave-receivingsensor systems 6, 8, 9, 10 mounted within the passenger compartment ofan automotive vehicle. Each set of sensor systems 6, 8, 9, 10 comprisesa transmitter and a receiver (or just a receiver in some cases), whichmay be integrated into a single unit or individual components separatedfrom one another. In this embodiment, the sensor system 6 is mounted onthe A-Pillar of the vehicle. The sensor system 9 is mounted on the upperportion of the B-Pillar. The sensor system 8 is mounted on the roofceiling portion or the headliner. The sensor system 10 is mounted nearthe middle of an instrument panel 17 in front of the driver's seat 3.

The sensor systems 6, 8, 9, 10 are preferably ultrasonic orelectromagnetic, although sensor systems 6, 8, 9, 10 can be any othertype of sensors which will detect the presence of an occupant from adistance including capacitive or electric field sensors. Also, if thesensor systems 6, 8, 9, 10 are passive infrared sensors, for example,then they may only comprise a wave-receiver. Recent advances in QuantumWell Infrared Photodetectors by NASA show great promise for thisapplication. See “Many Applications Possible For Largest QuantumInfrared Detector”, Goddard Space Center News Release Feb. 27, 2002.

The Quantum Well Infrared Photodetector is a new detector which promisesto be a low-cost alternative to conventional infrared detectortechnology for a wide range of scientific and commercial applications,and particularly for sensing inside and outside of a vehicle. The mainproblem that needs to be solved is that it operates at 76 degrees Kelvin(−323 degrees F.). Chips are being developed capable of cooling otherchips economically. It remains to be seen if these low temperatures canbe economically achieved.

A section of the passenger compartment of an automobile is showngenerally as 40 in FIGS. 8A-8D. A driver 30 of the vehicle sits on aseat 3 behind a steering wheel 42, which contains an airbag assembly 44.Airbag assembly 44 may be integrated into the steering wheel assembly orcoupled to the steering wheel 42. Five transmitter and/or receiverassemblies 49, 50, 51, 52 and 54 are positioned at various places in thepassenger compartment to determine the location of various parts of thedriver, e.g., the head, chest and torso, relative to the airbag and tootherwise monitor the interior of the passenger compartment. Monitoringof the interior of the passenger compartment can entail detecting thepresence or absence of the driver and passengers, differentiatingbetween animate and inanimate objects, detecting the presence ofoccupied or unoccupied child seats, rear-facing or forward-facing, andidentifying and ascertaining the identity of the occupying items in thepassenger compartment, a similar system can be used for monitoring theinterior of a truck, shipping container or other containers.

A processor such as control circuitry 20 is connected to thetransmitter/receiver assemblies 49, 50, 51, 52, 54 and controls thetransmission from the transmitters, if a transmission component ispresent in the assemblies, and captures the return signals from thereceivers, if a receiver component is present in the assemblies. Controlcircuitry 20 usually contains analog to digital converters (ADCs) or aframe grabber or equivalent, a microprocessor containing sufficientmemory and appropriate software including, for example, patternrecognition algorithms, and other appropriate drivers, signalconditioners, signal generators, etc. Usually, in any givenimplementation, only three or four of the transmitter/receiverassemblies would be used depending on their mounting locations asdescribed below. In some special cases, such as for a simpleclassification system, only a single or sometimes only twotransmitter/receiver assemblies are used.

A portion of the connection between the transmitter/receiver assemblies49, 50, 51, 52, 54 and the control circuitry 20, is shown as wires.These connections can be wires, either individual wires leading from thecontrol circuitry 20 to each of the transmitter/receiver assemblies 49,50, 51, 52, 54 or one or more wire buses or in some cases, wireless datatransmission can be used.

The location of the control circuitry 20 in the dashboard of the vehicleis for illustration purposes only and does not limit the location of thecontrol circuitry 20. Rather, the control circuitry 20 may be locatedanywhere convenient or desired in the vehicle.

It is contemplated that a system and method in accordance with theinvention can include a single transmitter and multiple receivers, eachat a different location. Thus, each receiver would not be associatedwith a transmitter forming transmitter/receiver assemblies. Rather, forexample, with reference to FIG. 8A, only element 51 could constitute atransmitter/receiver assembly and elements 49, 50, 52 and 54 could bereceivers only.

On the other hand, it is conceivable that in some implementations, asystem and method in accordance with the invention include a singlereceiver and multiple transmitters. Thus, each transmitter would not beassociated with a receiver forming transmitter/receiver assemblies.Rather, for example, with reference to FIG. 8A, only element 51 wouldconstitute a transmitter/receiver assembly and elements 49, 50, 52, 54would be transmitters only.

One ultrasonic transmitter/receiver as used herein is similar to thatused on modern auto-focus cameras such as manufactured by the PolaroidCorporation. Other camera auto-focusing systems use differenttechnologies, which are also applicable here, to achieve the samedistance to object determination. One camera system manufactured by Fujiof Japan, for example, uses a stereoscopic system which could also beused to determine the position of a vehicle occupant providing there issufficient light available. In the case of insufficient light, a sourceof infrared light can be added to illuminate the driver. In a relatedimplementation, a source of infrared light is reflected off of thewindshield and illuminates the vehicle occupant. An infrared receiver 56is located attached to the rear view mirror assembly 55, as shown inFIG. 8E. Alternately, the infrared can be sent by the device 50 andreceived by a receiver elsewhere. Since any of the devices shown inthese figures could be either transmitters or receivers or both, forsimplicity, only the transmitted and not the reflected wave fronts arefrequently illustrated.

When using the surface of the windshield as a reflector of infraredradiation (for transmitter/receiver assembly and element 52), care mustbe taken to assure that the desired reflectivity at the frequency ofinterest is achieved. Mirror materials, such as metals and other specialmaterials manufactured by Eastman Kodak, have a reflectivity forinfrared frequencies that is substantially higher than at visiblefrequencies. They are thus candidates for coatings to be placed on thewindshield surfaces for this purpose.

There are two preferred methods of implementing the vehicle interiormonitoring system of at least one of the inventions disclosed herein, amicroprocessor system and an application specific integrated circuitsystem (ASIC). Both of these systems are represented schematically as 20herein. In some systems, both a microprocessor and an ASIC are used. Inother systems, most if not all of the circuitry is combined onto asingle chip (system on a chip). The particular implementation depends onthe quantity to be made and economic considerations. A block diagramillustrating the microprocessor system is shown in FIG. 11A which showsthe implementation of the system of FIG. 1. An alternate implementationof the FIG. 1 system using an ASIC is shown in FIG. 11B. In both cases,the target, which may be a rear facing child seat, is shownschematically as 2 and the three transducers as 6, 8, and 10. In theembodiment of FIG. 11A, there is a digitizer coupled to the receivers 6,10 and the processor, and an indicator coupled to the processor. In theembodiment of FIG. 11B, there is a memory unit associated with the ASICand also an indicator coupled to the ASIC.

The position of the occupant may be determined in various ways includingby receiving and analyzing waves from a space in a passenger compartmentof the vehicle occupied by the occupant, transmitting waves to impactthe occupant, receiving waves after impact with the occupant andmeasuring time between transmission and reception of the waves,obtaining two or three-dimensional images of a passenger compartment ofthe vehicle occupied by the occupant and analyzing the images with anoptional focusing of the images prior to analysis, or by moving a beamof radiation through a passenger compartment of the vehicle occupied bythe occupant. The waves may be ultrasonic, radar, electromagnetic,passive infrared, and the like, and capacitive in nature. In the lattercase, a capacitance or capacitive sensor may be provided. An electricfield sensor could also be used.

Deployment of the airbag can be disabled when the determined position istoo close to the airbag.

The rate at which the airbag is inflated and/or the time in which theairbag is inflated may be determined based on the determined position ofthe occupant.

A system for controlling deployment of an airbag comprises a determiningsystem for determining the position of an occupant to be protected bydeployment of the airbag, a sensor system for assessing the probabilitythat a crash requiring deployment of the airbag is occurring, and acircuit coupled to the determining system, the sensor system and theairbag for enabling deployment of the airbag in consideration of thedetermined position of the occupant and the assessed probability that acrash is occurring. The circuit is structured and arranged to analyzethe assessed probability relative to a pre-determined threshold wherebydeployment of the airbag is enabled only when the assessed probabilityis greater than the threshold. Further, the circuit are arranged toadjust the threshold based on the determined position of the occupant.The determining system may be any of the determining systems discussedabove.

One method for controlling deployment of an airbag comprises a crashsensor for providing information on a crash involving the vehicle, aposition determining arrangement for determining the position of anoccupant to be protected by deployment of the airbag and a circuitcoupled to the airbag, the crash sensor and the position determiningarrangement and arranged to issue a deployment signal to the airbag tocause deployment of the airbag. The circuit is arranged to consider adeployment threshold which varies based on the determined position ofthe occupant. Further, the circuit is arranged to assess the probabilitythat a crash requiring deployment of the airbag is occurring and analyzethe assessed probability relative to the threshold whereby deployment ofthe airbag is enabled only when the assessed probability is greater thanthe threshold.

In another implementation, the sensor algorithm may determine the ratethat gas is generated to affect the rate at which the airbag isinflated. In all of these cases the position of the occupant is used toaffect the deployment of the airbag either as to whether or not itshould be deployed at all, the time of deployment or as to the rate ofinflation.

1.1 Ultrasonics

1.1.1 General

The maximum acoustic frequency that is practical to use for acousticimaging in the systems is about 40 to 160 kilohertz (kHz). Thewavelength of a 50 kHz acoustic wave is about 0.6 cm which is too coarseto determine the fine features of a person's face, for example. It iswell understood by those skilled in the art that features which are muchsmaller than the wavelength of the irradiating radiation cannot bedistinguished. Similarly, the wavelength of common radar systems variesfrom about 0.9 cm (for 33 GHz K band) to 133 cm (for 225 MHz P band)which are also too coarse for person-identification systems.

Referring now to FIGS. 5, 12 and 13, a section of the passengercompartment of an automobile is shown generally as 40 in FIG. 5. Adriver of a vehicle 30 sits on a seat 3 behind a steering wheel 42 whichcontains an airbag assembly 44. Four transmitter and/or receiverassemblies 50, 52, 53 and 54 are positioned at various places in oraround the passenger compartment to determine the location of the head,chest and torso of the driver 30 relative to the airbag assembly 44.Usually, in any given implementation, only one or two of thetransmitters and receivers would be used depending on their mountinglocations as described below.

FIG. 5 illustrates several of the possible locations of such devices.For example, transmitter and receiver 50 emits ultrasonic acousticalwaves which bounce off the chest of the driver 30 and return.Periodically, a burst of ultrasonic waves at about 50 kilohertz isemitted by the transmitter/receiver and then the echo, or reflectedsignal, is detected by the same or different device. An associatedelectronic circuit measures the time between the transmission and thereception of the ultrasonic waves and determines the distance from thetransmitter/receiver to the driver 30 based on the velocity of sound.This information can then be sent to a microprocessor that can belocated in the crash sensor and diagnostic circuitry which determines ifthe driver 30 is close enough to the airbag assembly 44 that adeployment might, by itself, cause injury to the driver 30. In such acase, the circuit disables the airbag system and thereby prevents itsdeployment. In an alternate case, the sensor algorithm assesses theprobability that a crash requiring an airbag is in process and waitsuntil that probability exceeds an amount that is dependent on theposition of the driver 30. Thus, for example, the sensor might decide todeploy the airbag based on a need probability assessment of 50%, if thedecision must be made immediately for a driver 30 approaching theairbag, but might wait until the probability rises to 95% for a moredistant driver. Although a driver system has been illustrated, thepassenger system would be similar.

Alternate mountings for the transmitter/receiver include variouslocations on the instrument panel on either side of the steering columnsuch as 53 in FIG. 5. Also, although some of the devices hereinillustrated assume that for the ultrasonic system, the same device isused for both transmitting and receiving waves, there are advantages inseparating these functions, at least for standard transducer systems.Since there is a time lag required for the system to stabilize aftertransmitting a pulse before it can receive a pulse, close measurementsare enhanced, for example, by using separate transmitters and receivers.In addition, if the ultrasonic transmitter and receiver are separated,the transmitter can transmit continuously, provided the transmittedsignal is modulated such that the received signal can be compared withthe transmitted signal to determine the time it takes for the waves toreach and reflect off of the occupant.

Many methods exist for this modulation including varying the frequencyor amplitude of the waves or pulse modulation or coding. In all cases,the logic circuit which controls the sensor and receiver must be able todetermine when the signal which was most recently received wastransmitted. In this manner, even though the time that it takes for thesignal to travel from the transmitter to the receiver, via reflectionoff of the occupant or other object to be monitored, may be severalmilliseconds, information as to the position of the occupant is receivedcontinuously which permits an accurate, although delayed, determinationof the occupant's velocity from successive position measurements. Othermodulation methods that may be applied to electromagnetic radiationsinclude TDMA, CDMA, noise or pseudo-noise, spatial, etc.

Conventional ultrasonic distance measuring devices must wait for thesignal to travel to the occupant or other monitored object and returnbefore a new signal is sent. This greatly limits the frequency at whichposition data can be obtained to the formula where the frequency isequal to the velocity of sound divided by two times the distance to theoccupant. For example, if the velocity of sound is taken at about 1000feet per second, occupant position data for an occupant or objectlocated one foot from the transmitter can only be obtained every 2milliseconds which corresponds to a frequency of about 500 Hz. At athree-foot displacement and allowing for some processing time, thefrequency is closer to about 100 Hz.

This slow frequency that data can be collected seriously degrades theaccuracy of the velocity calculation. The reflection of ultrasonic wavesfrom the clothes of an occupant or the existence of thermal gradients,for example, can cause noise or scatter in the position measurement andlead to significant inaccuracies in a given measurement. When manymeasurements are taken more rapidly, as in the technique described here,these inaccuracies can be averaged and a significant improvement in theaccuracy of the velocity calculation results.

The determination of the velocity of the occupant need not be derivedfrom successive distance measurements. A potentially more accuratemethod is to make use of the Doppler Effect where the frequency of thereflected waves differs from the transmitted waves by an amount which isproportional to the occupant's velocity. In one embodiment, a singleultrasonic transmitter and a separate receiver are used to measure theposition of the occupant, by the travel time of a known signal, and thevelocity, by the frequency shift of that signal. Although the DopplerEffect has been used to determine whether an occupant has fallen asleep,it has not previously been used in conjunction with a position measuringdevice to determine whether an occupant is likely to become out ofposition, i.e., an extrapolated position in the future based on theoccupant's current position and velocity as determined from successiveposition measurements, and thus in danger of being injured by adeploying airbag, or that a monitored object is moving. This combinationis particularly advantageous since both measurements can be accuratelyand efficiently determined using a single transmitter and receiver pairresulting in a low cost system.

One problem with Doppler measurements is the slight change in frequencythat occurs during normal occupant velocities. This requires thatsophisticated electronic techniques and a low Q receiver should beutilized to increase the frequency and thereby render it easier tomeasure the velocity using the phase shift. For many implementations,therefore, the velocity of the occupant is determined by calculating thedifference between successive position measurements.

The following discussion will apply to the case where ultrasonic sensorsare used although a similar discussion can be presented relative to theuse of electromagnetic sensors such as active infrared sensors, takinginto account the differences in the technologies. Also, the followingdiscussion will relate to an embodiment wherein the seat is the frontpassenger seat, although a similar discussion can apply to othervehicles and monitoring situations.

The ultrasonic or electromagnetic sensor systems 6, 8, 9 and 10 in FIG.7 can be controlled or driven, one at a time or simultaneously, by anappropriate driver circuit such as ultrasonic or electromagnetic sensordriver circuit 58 shown in FIG. 9. The transmitters of the ultrasonic orelectromagnetic sensor systems 6, 8, 9 and 10 transmit respectiveultrasonic or electromagnetic waves toward the seat 4 and transmitpulses (see FIG. 10( c)) in sequence at times t1, t2, t3 and t4(t4>t3>t2>t1) or simultaneously (t1=t2=t3=t4). The reflected waves ofthe ultrasonic or electromagnetic waves are received by the receiversChA-ChD of the ultrasonic or electromagnetic sensors 6, 8, 9 and 10. Thereceiver ChA is associated with the ultrasonic or electromagnetic sensorsystem 8, the receiver ChB is associated with the ultrasonic orelectromagnetic sensor system 5, the receiver ChC is associated with theultrasonic or electromagnetic sensor system 6, and the receiver ChD isassociated with the ultrasonic or electromagnetic sensor system 9.

FIGS. 10( a) and 10(b) show examples of the reflected ultrasonic wavesUSRW that are received by receivers ChA-ChD. FIG. 10( a) shows anexample of the reflected wave USRW that is obtained when an adult sitsin a normally seated space on the passenger seat 4, while FIG. 10( b)shows an example of the reflected wave USRW that are obtained when anadult sits in a slouching state (one of the abnormal seated-states) inthe passenger seat 4.

In the case of a normally seated passenger, as shown in FIGS. 6 and 7,the location of the ultrasonic sensor system 6 is closest to thepassenger A. Therefore, the reflected wave pulse P1 is received earliestafter transmission by the receiver ChD as shown in FIG. 10( a), and thewidth of the reflected wave pulse P1 is larger. Next, the distance fromthe ultrasonic sensor 8 is closer to the passenger A, so a reflectedwave pulse P2 is received earlier by the receiver ChA compared with theremaining reflected wave pulses P3 and P4. Since the reflected wavepauses P3 and P4 take more time than the reflected wave pulses P1 and P2to arrive at the receivers ChC and ChB, the reflected wave pulses P3 andP4 are received as the timings shown in FIG. 10( a). More specifically,since it is believed that the distance from the ultrasonic sensor system6 to the passenger A is slightly shorter than the distance from theultrasonic sensor system 10 to the passenger A, the reflected wave pulseP3 is received slightly earlier by the receiver ChC than the reflectedwave pulse P4 is received by the receiver ChB.

In the case where the passenger A is sitting in a slouching state in thepassenger seat 4, the distance between the ultrasonic sensor system 6and the passenger A is shortest. Therefore, the time from transmissionat time t3 to reception is shortest, and the reflected wave pulse P3 isreceived by the receiver ChC, as shown in FIG. 10( b). Next, thedistances between the ultrasonic sensor system 10 and the passenger Abecomes shorter, so the reflected wave pulse P4 is received earlier bythe receiver ChB than the remaining reflected wave pulses P2 and P1.When the distance from the ultrasonic sensor system 8 to the passenger Ais compared with that from the ultrasonic sensor system 9 to thepassenger A, the distance from the ultrasonic sensor system 8 to thepassenger A becomes shorter, so the reflected wave pulse P2 is receivedby the receiver ChA first and the reflected wave pulse P1 is thusreceived last by the receiver ChD.

The configurations of the reflected wave pulses P1-P4, the times thatthe reflected wave pulses P1-P4 are received, the sizes of the reflectedwave pulses P1-P4 are varied depending upon the configuration andposition of an object such as a passenger situated on the frontpassenger seat 4. FIGS. 10( a) and (b) merely show examples for thepurpose of description and therefore the present invention is notlimited to these examples.

The outputs of the receivers ChA-ChD, as shown in FIG. 9, are input to aband pass filter 60 through a multiplex circuit 59 which is switched insynchronization with a timing signal from the ultrasonic sensor drivecircuit 58. The band pass filter 60 removes a low frequency wavecomponent from the output signal based on each of the reflected waveUSRW and also removes some of the noise. The output signal based on eachof the reflected wave USRW is passed through the band pass filter 60,then is amplified by an amplifier 61. The amplifier 61 also removes thehigh frequency carrier wave component in each of the reflected wavesUSRW and generates an envelope wave signal. This envelope wave signal isinput to an analog/digital converter (ADC) 62 and digitized as measureddata. The measured data is input to a processing circuit 63, which iscontrolled by the timing signal which is in turn output from theultrasonic sensor drive circuit 58.

The processing circuit 63 collects measured data at intervals of 7 ms(or at another time interval with the time interval also being referredto as a time window or time period), and 47 data points are generatedfor each of the ultrasonic sensor systems 6, 8, 9 and 10. For each ofthese reflected waves USRW, the initial reflected wave portion T1 andthe last reflected wave portion T2 are cut off or removed in each timewindow. The reason for this will be described when the trainingprocedure of a neural network is described later, and the description isomitted for now. With this, 32, 31, 37 and 38 data points will besampled by the ultrasonic sensor systems 6, 8, 9 and 10, respectively.The reason why the number of data points differs for each of theultrasonic sensor systems 6, 8, 9 and 10 is that the distance from thepassenger seat 4 to the ultrasonic sensor systems 6, 8, 9 and 10 differfrom one another.

Each of the measured data is input to a normalization circuit 64 andnormalized. The normalized measured data is input to the neural network65 as wave data.

A comprehensive occupant sensing system will now be discussed whichinvolves a variety of different sensors, again this is for illustrationpurposes only and a similar description can be constructed for othervehicles including shipping container and truck trailer monitoring. Manyof these sensors will be discussed under the appropriate sections below.FIG. 6 shows a passenger seat 70 to which an adjustment apparatusincluding a seated-state detecting unit according to the presentinvention may be applied. The seat 70 includes a horizontally situatedbottom seat portion 4 and a vertically oriented back portion 72. Theseat portion 4 is provided with one or more pressure or weight sensors7, 76 that determine the weight of the object occupying the seat or thepressure applied by the object to the seat. The coupled portion betweenthe seated portion 4 and the back portion 72 is provided with areclining angle detecting sensor 57, which detects the tilted angle ofthe back portion 72 relative to the seat portion 4. The seat portion 4is provided with a seat track position-detecting sensor 74. The seattrack position detecting sensor 74 detects the quantity of movement ofthe seat portion 4 which is moved from a back reference position,indicated by the dotted chain line. Optionally embedded within the backportion 72 are a heartbeat sensor 71 and a motion sensor 73. Attached tothe headliner is a capacitance sensor 78. The seat 70 may be the driverseat, the front passenger seat or any other seat in a motor vehicle aswell as other seats in transportation vehicles or seats innon-transportation applications.

A pressure or weight measuring system such as the sensors 7 and 76 areassociated with the seat, e.g., mounted into or below the seat portion 4or on the seat structure, for measuring the pressure or weight appliedonto the seat. The pressure or weight may be zero if no occupying itemis present and the sensors are calibrated to only measure incrementalweight or pressure. Sensors 7 and 76 may represent a plurality ofdifferent sensors which measure the pressure or weight applied onto theseat at different portions thereof or for redundancy purposes, e.g.,such as by means of an airbag or fluid filled bladder 75 in the seatportion 4. Airbag or bladder 75 may contain a single or a plurality ofchambers, each of which may be associated with a sensor (transducer) 76for measuring the pressure in the chamber. Such sensors may be in theform of strain, force or pressure sensors which measure the force orpressure on the seat portion 4 or seat back 72, a part of the seatportion 4 or seat back 72, displacement measuring sensors which measurethe displacement of the seat surface or the entire seat 70 such asthrough the use of strain gages mounted on the seat structural members,such as 7, or other appropriate locations, or systems which convertdisplacement into a pressure wherein one or more pressure sensors can beused as a measure of weight and/or weight distribution. Sensors 7, 76may be of the types disclosed in U.S. Pat. No. 6,242,701 and below.Although pressure or weight here is disclosed and illustrated withregard to measuring the pressure applied by or weight of an objectoccupying a seat in an automobile or truck, the same principles can beused to measure the pressure applied by and weight of objects occupyingother vehicles including truck trailers and shipping containers. Forexample, a series of fluid filled bladders under a segmented floor couldbe used to measure the weight and weight distribution in a trucktrailer.

Many practical problems have arisen during the development stages ofbladder and strain gage based weight systems. Some of these problemsrelate to bladder sensors and in particular to gas-filled bladdersensors and are effectively dealt with in U.S. Pat. No. 5,918,696, U.S.Pat. No. 5,927,427, U.S. Pat. No. 5,957,491, U.S. Pat. No. 5,979,585,U.S. Pat. No. 5,984,349, U.S. Pat. No. 6,021,863, U.S. Pat. No.6,056,079, U.S. Pat. No. 6,076,853, U.S. Pat. No. 6,260,879 and U.S.Pat. No. 6,286,861. Other problems relate to seatbelt usage and tounanticipated stresses and strains that occur in seat mountingstructures and will be discussed below.

As illustrated in FIG. 9, the output of the pressure or weight sensor(s)7 and 76 is amplified by an amplifier 66 coupled to the pressure orweight sensor(s) 7,76 and the amplified output is input to theanalog/digital converter 67.

A heartbeat sensor 71 is arranged to detect a heartbeat, and themagnitude thereof, of a human occupant of the seat, if such a humanoccupant is present. The output of the heartbeat sensor 71 is input tothe neural network 65. The heartbeat sensor 71 may be of the type asdisclosed in McEwan (U.S. Pat. Nos. 5,573,012 and 5,766,208). Theheartbeat sensor 71 can be positioned at any convenient positionrelative to the seat 4 where occupancy is being monitored. A preferredlocation is within the vehicle seatback. The heartbeat of a stowaway ina cargo container or truck trailer can similarly be measured be a sensoron the vehicle floor or other appropriate location that measuresvibrations.

The reclining angle detecting sensor 57 and the seat trackposition-detecting sensor 74, which each may comprise a variableresistor, can be connected to constant-current circuits, respectively. Aconstant-current is supplied from the constant-current circuit to thereclining angle detecting sensor 57, and the reclining angle detectingsensor 57 converts a change in the resistance value on the tilt of theback portion 72 to a specific voltage. This output voltage is input toan analog/digital converter 68 as angle data, i.e., representative ofthe angle between the back portion 72 and the seat portion 4. Similarly,a constant current can be supplied from the constant-current circuit tothe seat track position-detecting sensor 74 and the seat track positiondetecting sensor 74 converts a change in the resistance value based onthe track position of the seat portion 4 to a specific voltage. Thisoutput voltage is input to an analog/digital converter 69 as seat trackdata. Thus, the outputs of the reclining angle-detecting sensor 57 andthe seat track position-detecting sensor 74 are input to theanalog/digital converters 68 and 69, respectively. Each digital datavalue from the ADCs 68, 69 is input to the neural network 65. Althoughthe digitized data of the pressure or weight sensor(s) 7, 76 is input tothe neural network 65, the output of the amplifier 66 is also input to acomparison circuit. The comparison circuit, which is incorporated in thegate circuit algorithm, determines whether or not the weight of anobject on the passenger seat 70 is more than a predetermined weight,such as 60 lbs., for example. When the weight is more than 60 lbs., thecomparison circuit outputs a logic 1 to the gate circuit to be describedlater. When the weight of the object is less than 60 lbs., a logic 0 isoutput to the gate circuit. A more detailed description of this andsimilar systems can be found in the numerous patents and patentapplications assigned to the current assignee, Automotive TechnologiesInternational, Inc., and in the description below. The system describedabove is one example of many systems that can be designed using theteachings of at least one of the inventions disclosed herein fordetecting the occupancy state of the seat of a vehicle.

As diagrammed in FIG. 14, the first step is to mount the four sets ofultrasonic sensor systems 11-14, the weight sensors 7,76, the recliningangle detecting sensor 57, and the seat track position detecting sensor74, for example, into a vehicle (step S1). For other vehicle monitoringtasks different sets of sensors could be used. Next, in order to providedata for the neural network 65 to learn the patterns of seated states,data is recorded for patterns of all possible seated or occupancy statesand a list is maintained recording the seated or occupancy states forwhich data was acquired. The data from the sensors/transducers 6, 8, 9,10, 57, 71, 73, 74, 76 and 78 for a particular occupancy of thepassenger seat, for example, is called a vector (step S2). It should bepointed out that the use of the reclining angle detecting sensor 57,seat track position detecting sensor 74, heartbeat sensor 71, capacitivesensor 78 and motion sensor 73 is not essential to the detectingapparatus and method in accordance with the invention. However, each ofthese sensors, in combination with any one or more of the other sensorsenhances the evaluation of the seated-state of the seat or the occupancyof the vehicle.

Next, based on the training data from the reflected waves of theultrasonic sensor systems 6, 8, 9, 10 and the other sensors 7, 71, 73,76, 78 the vector data is collected (step S3). Next, the reflected wavesP1-P4 are modified by removing the initial reflected waves from eachtime window with a short reflection time from an object (range gating)and the last portion of the reflected waves from each time window with along reflection time from an object (step S4). It is believed that thereflected waves with a short reflection time from an object is due tocross-talk, that is, waves from the transmitters which leak into each oftheir associated receivers ChA-ChD. It is also believed that thereflected waves with a long reflection time are reflected waves from anobject far away from the passenger seat or from multipath reflections.If these two reflected wave portions are used as data, they will addnoise to the training process. Therefore, these reflected wave portionsare eliminated from the data.

Recent advances in ultrasonic transducer design have now permitted theuse of a single transducer acting as both a sender (transmitter) andreceiver. These same advances have substantially reduced the ringing ofthe transducer after the excitation pulse has been caused to die out towhere targets as close as about 2 inches from the transducer can besensed. Thus, the magnitude of the T1 time period has been substantiallyreduced.

As shown in FIG. 15A, the measured data is normalized by making thepeaks of the reflected wave pulses P1-P4 equal (step S5). Thiseliminates the effects of different reflectivities of different objectsand people depending on the characteristics of their surfaces such astheir clothing. Data from the weight sensor, seat track position sensorand seat reclining angle sensor is also frequently normalized basedtypically on fixed normalization parameters. When other sensors are usedfor other types of monitoring, similar techniques are used.

The data from the ultrasonic transducers are now also preferably fedthrough a logarithmic compression circuit that substantially reduces themagnitude of reflected signals from high reflectivity targets comparedto those of low reflectivity. Additionally, a time gain circuit is usedto compensate for the difference in sonic strength received by thetransducer based on the distance of the reflecting object from thetransducer.

As various parts of the vehicle interior identification and monitoringsystem described in the above referenced patents and patent applicationsare implemented, a variety of transmitting and receiving transducerswill be present in the vehicle passenger compartment. If several ofthese transducers are ultrasonic transmitters and receivers, they can beoperated in a phased array manner, as described elsewhere for theheadrest, to permit precise distance measurements and mapping of thecomponents of the passenger compartment. This is illustrated in FIG. 16which is a perspective view of the interior of the passenger compartmentshowing a variety of transmitters and receivers, 6, 8, 9, 23, 49-51which can be used in a sort of phased array system. In addition,information can be transmitted between the transducers using codedsignals in an ultrasonic network through the vehicular compartmentairspace. If one of these sensors is an optical CCD or CMOS array, thelocation of the driver's eyes can be accurately determined and theresults sent to the seat ultrasonically. Obviously, many otherpossibilities exist for automobile and other vehicle monitoringsituations.

To use ultrasonic transducers in a phase array mode generally requiresthat the transducers have a low Q. Certain new micromachined capacitivetransducers appear to be suitable for such an application. The range ofsuch transducers is at present limited, however.

The speed of sound varies with temperature, humidity, and pressure. Thiscan be compensated for by using the fact that the geometry between thetransducers is known and the speed of sound can therefore be measured.Thus, on vehicle startup and as often as desired thereafter, the speedof sound can be measured by one transducer, such as transducer 18 inFIG. 17, sending a signal which is directly received by anothertransducer 5. Since the distance separating them is known, the speed ofsound can be calculated and the system automatically adjusted to removethe variation due to variations in the speed of sound. Therefore, thesystem operates with same accuracy regardless of the temperature,humidity or atmospheric pressure. It may even be possible to use thistechnique to also automatically compensate for any effects due to windvelocity through an open window. An additional benefit of this system isthat it can be used to determine the vehicle interior temperature foruse by other control systems within the vehicle since the variation inthe velocity of sound is a strong function of temperature and a weakfunction of pressure and humidity.

The problem with the speed of sound measurement described above is thatsome object in the vehicle may block the path from one transducer to theother. This of course could be checked and a correction would not bemade if the signal from one transducer does not reach the othertransducer. The problem, however, is that the path might not becompletely blocked but only slightly blocked. This would cause theultrasonic path length to increase, which would give a false indicationof a temperature change. This can be solved by using more than onetransducer. All of the transducers can broadcast signals to all of theother transducers. The problem here, of course, is which transducer pairshould be believed if they all give different answers. The answer is theone that gives the shortest distance or the greatest calculated speed ofsound. By this method, there are a total of 6 separate paths for fourultrasonic transducers.

An alternative method of determining the temperature is to use thetransducer circuit to measure some parameter of the transducer thatchanges with temperature. For example, the natural frequency ofultrasonic transducers changes in a known manner with temperature andtherefore by measuring the natural frequency of the transducer, thetemperature can be determined. Since this method does not requirecommunication between transducers, it would also work in situationswhere each transducer has a different resonant frequency.

The process, by which all of the distances are carefully measured fromeach transducer to the other transducers, and the algorithm developed todetermine the speed of sound, is a novel part of the teachings of theinstant invention for use with ultrasonic transducers. Prior to this,the speed of sound calculation was based on a single transmission fromone transducer to a known second transducer. This resulted in aninaccurate system design and degraded the accuracy of systems in thefield.

If the electronic control module that is part of the system is locatedin generally the same environment as the transducers, another method ofdetermining the temperature is available. This method utilizes a deviceand whose temperature sensitivity is known and which is located in thesame box as the electronic circuit. In fact, in many cases, an existingcomponent on the printed circuit board can be monitored to give anindication of the temperature. For example, the diodes in a logcomparison circuit have characteristics that their resistance changes ina known manner with temperature. It can be expected that the electronicmodule will generally be at a higher temperature than the surroundingenvironment, however, the temperature difference is a known andpredictable amount. Thus, a reasonably good estimation of thetemperature in the passenger compartment, or other containercompartment, can also be obtained in this manner. Thermisters or othertemperature transducers can be used.

The placement of ultrasonic transducers for the example of ultrasonicoccupant position sensor system of at least one of the inventionsdisclosed herein include the following novel disclosures: (1) theapplication of two sensors to single-axis monitoring of target volumes;(2) the method of locating two sensors spanning a target volume to senseobject positions, that is, transducers are mounted along the sensingaxis beyond the objects to be sensed; (3) the method of orientation ofthe sensor axis for optimal target discrimination parallel to the axisof separation of distinguishing target features; and (4) the method ofdefining the head and shoulders and supporting surfaces as defininghumans for rear facing child seat detection and forward facing humandetection.

A similar set of observations is available for the use ofelectromagnetic, capacitive, electric field or other sensors and forother vehicle monitoring situations. Such rules however must take intoaccount that some of such sensors typically are more accurate inmeasuring lateral and vertical dimensions relative to the sensor thandistances perpendicular to the sensor. This is particularly the case forCMOS and CCD-based transducers.

Considerable work is ongoing to improve the resolution of the ultrasonictransducers. To take advantage of higher resolution transducers, datapoints should be obtained that are closer together in time. This meansthat after the envelope has been extracted from the returned signal, thesampling rate should be increased from approximately 1000 samples persecond to perhaps 2000 samples per second or even higher. By doubling ortripling the amount of data required to be analyzed, the system which ismounted on the vehicle will require greater computational power. Thisresults in a more expensive electronic system. Not all of the data is ofequal importance, however. The position of the occupant in the normalseating position does not need to be known with great accuracy whereas,as that occupant is moving toward the keep out zone boundary duringpre-crash braking, the spatial accuracy requirements become moreimportant. Fortunately, the neural network algorithm generating systemhas the capability of indicating to the system designer the relativevalue of each data point used by the neural network. Thus, as many as,for example, 500 data points per vector may be collected and fed to theneural network during the training stage and, after careful pruning, thefinal number of data points to be used by the vehicle mounted system maybe reduced to 150, for example. This technique of using the neuralnetwork algorithm-generating program to prune the input data is animportant teaching of the present invention.

By this method, the advantages of higher resolution transducers can beoptimally used without increasing the cost of the electronicvehicle-mounted circuits. Also, once the neural network has determinedthe spacing of the data points, this can be fine-tuned, for example, byacquiring more data points at the edge of the keep out zone as comparedto positions well into the safe zone. The initial technique is done bycollecting the full 500 data points, for example, while in the systeminstalled in the vehicle the data digitization spacing can be determinedby hardware or software so that only the required data is acquired.

1.1.2 Thermal Gradients

Techniques for compensating for thermal gradients which affectultrasonic waves and electromagnetic waves are set forth in U.S. patentapplication Ser. No. 10/940,881. Some of that disclosure is set forthbelow.

Thermal gradients adversely affect optics (e.g., create mirages) buttypically do so to a lesser extent than they affect ultrasonic waves.

For example, an optical system used in a vehicle, in the same manner asan ultrasonic system is used as discussed above, may include a highdynamic range camera (HDRC). HDRC's are known devices to those skilledin the art. In accordance with the invention, the HDRC can be coupled toa log compression amplifier so that the log compression amplifieramplifies some electromagnetic waves received by the HDRC relative toothers. Thus, in this embodiment, the log compression amplifier wouldcompensate for thermal instability affecting the propagation ofelectromagnetic waves within the vehicle interior. Some HDRC cameras arealready designed to have this log compression built in such as onedeveloped by Fraunhofer-Inst. of Microelectron. Circuits & Systems inDuisburg, Germany. An alternate approach using a combination ofspatially varying images is described in International Application No.WO 00/79784 assigned to Columbia University.

Although the above discussion has centered on the front passenger seat,it is obvious that the same or similar apparatus can be used for thedriver seat as well as the rear seats. Although attention has beenfocused of frontal protection airbags, again the apparatus can beapplied to solving similar problems in side and rear impacts and tocontrol the deployment of other occupant restraints in addition toairbags. Thus, to reiterate some of the more novel features of theinvention, this application discloses: (1) the use of a tubular mountingstructure for the transducers; (2) the use of electronic reduction orsuppression of transducer ringing; (3) the use of mechanical damping ofthe transducer cone, all three of which permits the use of a singletransducer for both sending and receiving; (4) the use of a shaped hornto control the pattern of ultrasound; (5) the use of the resonantfrequency monitoring principle to permit speed of sound compensation;(6) the use of multiple frequencies with sufficient spacing to isolatethe signals from each other; (7) the ability to achieve a completeneural network update using four transducers every 10 to 20milliseconds; (8) the ability to package the transducer and tube into asmall package due to the ability to use a small diameter tube fortransmission with minimal signal loss; (9) the use of a logarithmiccompression amplifier to minimize the effects of thermal gradients inthe vehicle; and (10) the significant cost reduction and performanceimprovement which results from the applications of the above principles.To the extent possible, the foregoing features can be used incombination with one another.

1.2 Optics

In FIG. 4, the ultrasonic transducers of the previous designs arereplaced by laser transducers 8 and 9 which are connected to amicroprocessor 20. In all other manners, the system operates the same.The design of the electronic circuits for this laser system is describedin U.S. Pat. No. 5,653,462 and in particular FIG. 8 thereof and thecorresponding description. In this case, a pattern recognition systemsuch as a neural network system is employed and uses the demodulatedsignals from the laser transducers 8 and 9.

A more complicated and sophisticated system is shown conceptually inFIG. 5 where transmitter/receiver assembly 52 is illustrated. In thiscase, as described briefly above, an infrared transmitter and a pair ofoptical receivers are used to capture the reflection of the passenger.When this system is used to monitor the driver as shown in FIG. 5, withappropriate circuitry and a microprocessor, the behavior of the drivercan be monitored. Using this system, not only can the position andvelocity of the driver be determined and used in conjunction with anairbag system, but it is also possible to determine whether the driveris falling asleep or exhibiting other potentially dangerous behavior bycomparing portions of his/her image over time. In this case, the speedof the vehicle can be reduced or the vehicle even stopped if this actionis considered appropriate. This implementation has the highestprobability of an unimpeded view of the driver since he/she must have aclear view through the windshield in order to operate the motor vehicle.

The output of microprocessor 20 of the monitoring system is shownconnected schematically to a general interface 36 which can be thevehicle ignition enabling system; the entertainment system; the seat,mirror, suspension or other adjustment systems; telematics or any otherappropriate vehicle system.

FIG. 8A illustrates a typical wave pattern of transmitted infrared wavesfrom transmitter/receiver assembly 49, which is mounted on the side ofthe vehicle passenger compartment above the front, driver's side door.Transmitter/receiver assembly 51, shown overlaid ontotransmitter/receiver 49, is actually mounted in the center headliner ofthe passenger compartment (and thus between the driver's seat and thefront passenger seat), near the dome light, and is aimed toward thedriver. Typically, there will be a symmetrical installation for thepassenger side of the vehicle. That is, a transmitter/receiver assemblywould be arranged above the front, passenger side door and anothertransmitter/receiver assembly would be arranged in the center headliner,near the dome light, and aimed toward the front, passenger side door.Additional transducers can be mounted in similar places for monitoringboth rear seat positions, another can be used for monitoring the trunkor any other interior volumes. As with the ultrasonic installations,most of the examples below are for automobile applications since theseare generally the most complicated. Nevertheless, at least one of theinventions disclosed herein is not limited to automobile vehicles andsimilar but generally simpler designs apply to other vehicles such asshipping containers, railroad cars and truck trailers.

In a preferred embodiment, each transmitter/receiver assembly 49, 51comprises an optical transducer, which may be a camera and an LED, thatwill frequently be used in conjunction with other opticaltransmitter/receiver assemblies such as shown at 50, 52 and 54, whichact in a similar manner. In some cases, especially when a low costsystem is used primarily to categorize the seat occupancy, a single ordual camera installation is used. In many cases, the source ofillumination is not co-located with the camera. For example, in onepreferred implementation, two cameras such as 49 and 51 are used with asingle illumination source located at 49.

These optical transmitter/receiver assemblies frequently comprise anoptical transmitter, which may be an infrared LED (or possibly a nearinfrared (NIR) LED), a laser with a diverging lens or a scanning laserassembly, and a receiver such as a CCD or CMOS array and particularly anactive pixel CMOS camera or array or a HDRL or HDRC camera or array asdiscussed below. The transducer assemblies map the location of theoccupant(s), objects and features thereof, in a two or three-dimensionalimage as will now be described.

Optical transducers using CCD arrays are now becoming price competitiveand, as mentioned above, will soon be the technology of choice forinterior vehicle monitoring. A single CCD array of 160 by 160 pixels,for example, coupled with the appropriate trained pattern recognitionsoftware, can be used to form an image of the head of an occupant andaccurately locate the head, eyes, ears etc. for some of the purposes ofat least one of the inventions disclosed herein.

In one embodiment, the microprocessor 20 includes one or more a trainedpattern recognition algorithms which have been trained using data aboutknown locations of the head and facial features of occupants indifferent positions and images from CCD arrays of, or more generallywaves received by wave-receiving transducers from, the passengercompartment when the occupants in the different positions are present.For example, during training, occupants are placed in the seat and wavesare received to create a data set, with the location of the headrelative to the passenger compartment being provided to the patternrecognition algorithm generating software. The occupant moves and wavesare again received to create another data set. This process continuesfor that occupant and then for different occupants. The data sets areinput to the pattern recognition algorithm generating software toprovide a pattern recognition algorithm which can operatively receive asinput waves or signals representative thereof and provide the locationof the head relative to the passenger compartment as output, and inferthe location of the eyes relative to the passenger compartment from thelocation of the head.

The location or position of the occupant can be determined in variousways as noted and listed above and below as well. Generally, any type ofoccupant sensor can be used. Some particular occupant sensors which canbe used in the systems and methods in accordance with the invention.Specifically, a camera or other device for obtaining images of apassenger compartment of the vehicle occupied by the occupant andanalyzing the images can be mounted at the locations of the transmitterand/or receiver assemblies 49, 50, 51, and 54 in FIG. 8C. The camera orother device may be constructed to obtain three-dimensional imagesand/or focus the images on one or more optical arrays such as CCDs.Further, a mechanism for moving a beam of radiation through a passengercompartment of the vehicle occupied by the occupant, i.e., a scanningsystem, can be used. When using ultrasonic or electromagnetic waves, thetime of flight between the transmission and reception of the waves canbe used to determine the position of the occupant. The occupant sensorcan also be arranged to receive infrared radiation from a space in apassenger compartment of the vehicle occupied by the occupant. It canalso comprise an electric field sensor operative in a seat occupied bythe occupant or a capacitance sensor operative in a seat occupied by theoccupant. The implementation of such sensors in the invention will bereadily appreciated by one skilled in the art in view of the disclosureherein of general occupant sensors for sensing the position of theoccupant using waves, energy or radiation.

Looking now at FIG. 18, a schematic illustration of a system forcontrolling operation of a vehicle based on recognition of an authorizedindividual in accordance with the invention is shown. One or more imagesof the passenger compartment 105 are received at 106 and data derivedtherefrom at 107. Multiple image receivers may be provided at differentlocations. The data derivation may entail any one or more of numeroustypes of image processing techniques such as those described in U.S.Pat. No. 6,397,136 including those designed to improve the clarity ofthe image. A pattern recognition algorithm, e.g., a neural network, istrained in a training phase 108 to recognize authorized individuals. Thetraining phase can be conducted upon purchase of the vehicle by thedealer or by the owner after performing certain procedures provided tothe owner, e.g., entry of a security code or key. In the case of theoperator of a truck or when such an operator takes possession of atrailer or cargo container, the identity of the operator can be sent bytelematics to a central station for recording and perhaps furtherprocessing.

In the training phase for a theft prevention system, the authorizeddriver(s) would sit themselves in the driver or passenger seat andoptical images would be taken and processed to obtain the patternrecognition algorithm. A processor 109 is embodied with the patternrecognition algorithm thus trained to identify whether a person is theauthorized individual by analysis of subsequently obtained data derivedfrom optical images. The pattern recognition algorithm in processor 109outputs an indication of whether the person in the image is anauthorized individual for which the system is trained to identify. Asecurity system 110 enables operations of the vehicle when the patternrecognition algorithm provides an indication that the person is anindividual authorized to operate the vehicle and prevents operation ofthe vehicle when the pattern recognition algorithm does not provide anindication that the person is an individual authorized to operate thevehicle.

Optionally, an optical transmitting unit 111 is provided to transmitelectromagnetic energy into the passenger compartment, or other volumein the case of other vehicles, such that electromagnetic energytransmitted by the optical transmitting unit is reflected by the personand received by the optical image reception device 106.

As noted above, several different types of optical reception devices canbe used including a CCD array, a CMOS array, focal plane array (FPA),Quantum Well Infrared Photodetector (QWIP), any type of two-dimensionalimage receiver, any type of three-dimensional image receiver, an activepixel camera and an HDRC camera.

The processor 109 can be trained to determine the position of theindividuals included in the images obtained by the optical imagereception device, as well as the distance between the optical imagereception devices and the individuals.

Instead of a security system, another component in the vehicle can beaffected or controlled based on the recognition of a particularindividual. For example, the rear view mirror, seat, seat belt anchoragepoint, headrest, pedals, steering wheel, entertainment system, ridequality, air-conditioning/ventilation system can be adjusted.

FIG. 20 shows the components of the manner in which an environment ofthe vehicle, designated 100, is monitored. The environment may either bean interior environment (car, trailer, truck, shipping container,railroad car), the entire passenger compartment or only a part thereof,or an exterior environment. An active pixel camera 101 obtains images ofthe environment and provides the images or a representation thereof, ordata derived therefrom, to a processor 102. The processor 102 determinesat least one characteristic of an object in the environment based on theimages obtained by the active pixel camera 101, e.g., the presence of anobject in the environment, the type of object in the environment, theposition of an object in the environment, the motion of an object in theenvironment and the velocity of an object in the environment. Theenvironment can be any vehicle environment. Several active pixel camerascan be provided, each focusing on a different area of the environment,although some overlap is desired. Instead of an active pixel camera orarray, a single light-receiving pixel can be used in some cases.

Systems based on ultrasonics and neural networks have been verysuccessful in analyzing the seated-state of both the passenger anddriver seats of automobiles. Such systems are now going into productionfor preventing airbag deployment when a rear facing child seat or andout-of-position occupant is present. The ultrasonic systems, however,suffer from certain natural limitations that prevent system accuracyfrom getting better than about 99 percent. These limitations relate tothe fact that the wavelength of ultrasound is typically between 3 mm and8 mm. As a result, unexpected results occur which are due partially tothe interference of reflections from different surfaces. Additionally,commercially available ultrasonic transducers are tuned devices thatrequire several cycles before they transmit significant energy andsimilarly require several cycles before they effectively receive thereflected signals. This requirement has the effect of smearing theresolution of the ultrasound to the point that, for example, using aconventional 40 kHz transducer, the resolution of the system isapproximately three inches.

In contrast, the wavelength of near infrared is less than one micron andno significant interferences occur. Similarly, the system is not tunedand therefore is theoretically sensitive to a very few cycles. As aresult, resolution of the optical system is determined by the pixelspacing in the CCD or CMOS arrays. For this application, typical arrayshave been chosen to be 100 pixels by 100 pixels and therefore the spacebeing imaged can be broken up into pieces that are significantly lessthan 1 cm in size. If greater resolution is required, arrays havinglarger numbers of pixels are readily available. Another advantage ofoptical systems is that special lenses can be used to magnify thoseareas where the information is most critical and operate at reducedresolution where this is not the case. For example, the area closest tothe at-risk zone in front of the airbag can be magnified.

To summarize, although ultrasonic neural network systems are operatingwith high accuracy, they do not totally eliminate the problem of deathsand injuries caused by airbag deployments. Optical systems, on the otherhand, at little or no increase in cost, have the capability of virtually100 percent accuracy. Additional problems of ultrasonic systems arisefrom the slow speed of sound and diffraction caused by variations is airdensity. The slow sound speed limits the rate at which data can becollected and thus eliminates the possibility of tracking the motion ofan occupant during a high speed crash.

In an embodiment wherein electromagnetic energy is used, it is to beappreciated that any portion of the electromagnetic signals thatimpinges upon a body portion of the occupant is at least partiallyabsorbed by the body portion. Sometimes, this is due to the fact thatthe human body is composed primarily of water, and that electromagneticenergy at certain frequencies can be readily absorbed by water. Theamount of electromagnetic signal absorption is related to the frequencyof the signal, and size or bulk of the body portion that the signalimpinges upon. For example, a torso of a human body tends to absorb agreater percentage of electromagnetic energy as compared to a hand of ahuman body for some frequencies.

Thus, when electromagnetic waves or energy signals are transmitted by atransmitter, the returning waves received by a receiver provide anindication of the absorption of the electromagnetic energy. That is,absorption of electromagnetic energy will vary depending on the presenceor absence of a human occupant, the occupant's size, bulk, etc., so thatdifferent signals will be received relating to the degree or extent ofabsorption by the occupying item on a seat or elsewhere in the vehicle.The receiver will produce a signal representative of the returned wavesor energy signals which will thus constitute an absorption signal as itcorresponds to the absorption of electromagnetic energy by the occupyingitem in the seat.

Another optical infrared transmitter and receiver assembly is showngenerally at 52 in FIG. 5 and is mounted onto the instrument panelfacing the windshield. Although not shown in this view, reference 52consists of three devices, one transmitter and two receivers, one oneach side of the transmitter. In this case, the windshield is used toreflect the illumination light, and also the light reflected back by thedriver, in a manner similar to the “heads-up” display which is now beingoffered on several automobile models. The “heads-up” display, of course,is currently used only to display information to the driver and is notused to reflect light from the driver to a receiver. In this case, thedistance to the driver is determined stereoscopically through the use ofthe two receivers. In its most elementary sense, this system can be usedto measure the distance between the driver and the airbag module. Inmore sophisticated applications, the position of the driver, andparticularly of the driver's head, can be monitored over time and anybehavior, such as a drooping head, indicative of the driver fallingasleep or of being incapacitated by drugs, alcohol or illness can bedetected and appropriate action taken. Other forms of radiationincluding visual light, radar, terahertz and microwaves as well as highfrequency ultrasound could also be used by those skilled in the art.

A passive infrared system could be used to determine the position of anoccupant relative to an airbag or even to detect the presence of a humanor other life form in a vehicle. Passive infrared measures the infraredradiation emitted by the occupant and compares it to the background. Assuch, unless it is coupled with an imager and a pattern recognitionsystem, it can best be used to determine that an occupant is movingtoward the airbag since the amount of infrared radiation would then beincreasing. Therefore, it could be used to estimate the velocity of theoccupant but not his/her position relative to the airbag, since theabsolute amount of such radiation will depend on the occupant's size,temperature and clothes as well as on his position. When passiveinfrared is used in conjunction with another distance measuring system,such as the ultrasonic system described above, the combination would becapable of determining both the position and velocity of the occupantrelative to the airbag. Such a combination would be economical sinceonly the simplest circuits would be required. In one implementation, forexample, a group of waves from an ultrasonic transmitter could be sentto an occupant and the reflected group received by a receiver. Thedistance to the occupant would be proportional to the time between thetransmitted and received groups of waves and the velocity determinedfrom the passive infrared system. This system could be used in any ofthe locations illustrated in FIG. 5 as well as others not illustratedincluding truck trailers and cargo containers.

Recent advances in Quantum Well Infrared Photodetectors (QWIP) areparticularly applicable here due to the range of frequencies that theycan be designed to sense (3-18 microns) which encompasses the radiationnaturally emitted by the human body. Currently, QWIPs need to be cooledand thus are not quite ready for vehicle applications. There are,however, longer wave IR detectors based of focal plane arrays (FPA) thatare available in low resolution now. As the advantages of SWIR, MWIR andLWIR become more evident, devices that image in this part of theelectromagnetic spectrum will become more available.

Passive infrared could also be used effectively in conjunction with apattern recognition system. In this case, the passive infrared radiationemitted from an occupant can be focused onto a QWIP or FPA or even a CCDarray, in some cases, and analyzed with appropriate pattern recognitioncircuitry, or software, to determine the position of the occupant. Sucha system could be mounted at any of the preferred mounting locationsshown in FIG. 5 as well as others not illustrated.

Lastly, it is possible to use a modulated scanning beam of radiation anda single pixel receiver, PIN or avalanche diode, in the inventionsdescribed above. Any form of energy or radiation used above may also bein the infrared or radar spectrums and may be polarized and filters maybe used in the receiver to block out sunlight etc. These filters may benotch filters and may be made integral with the lens as one or morecoatings on the lens surface as is well known in the art. Note, in manyapplications, this may not be necessary as window glass blocks all IRexcept the near IR.

For some cases, such as a laser transceiver that may contain a CMOSarray, CCD, PIN or avalanche diode or other light sensitive devices, ascanner is also required that can be either solid state as in the caseof some radar systems based on a phased array, an acoustical opticalsystem as is used by some laser systems, or a mirror or MEMS basedreflecting scanner, or other appropriate technology. In one embodiment,controllable scanning using MEMS mirrors or other flexible ordistortable mirrors is used.

An optical classification system using a single or dual camera designwill now be discussed, although more than two cameras can also be usedin the system described below. The occupant sensing system shouldperform occupant classification as well as position tracking since bothare critical information for making decision of airbag deployment in anauto accident. For other purposes such as container or truck trailermonitoring generally only classification is required. FIG. 21 shows apreferred occupant sensing strategy. Occupant classification may be donestatically since the type of occupant does not change frequently.Position tracking, however, has to be done dynamically so that theoccupant can be tracked reliably during pre-crash braking situations.Position tracking should provide continuous position information so thatthe speed and the acceleration of the occupant can be estimated and aprediction can be made even before the next actual measurement takesplace.

The current assignee has demonstrated that occupant classification anddynamic position tracking can be done with a stand-alone optical systemthat uses a single camera. The same image information is processed in asimilar fashion for both classification and dynamic position tracking.As shown in FIG. 22, the whole process can involve five steps: imageacquisition, image preprocessing, feature extraction, neural networkprocessing, and post-processing. These steps will now be discussed.

Step-1 image acquisition is to obtain the image from the imaginghardware. The imaging hardware main components may include one or moreof the following image acquisition devices, a digital CMOS camera, ahigh-power near-infrared LED, and the LED control circuit. A pluralityof such image acquisition devices can be used. This step also includesimage brightness detection and LED control for illumination. Note thatthe image brightness detection and LED control do not have to beperformed for every frame. For example, during a specific interval, theECU can turn the LED ON and OFF and compare the resulting images. If theimage with LED ON is significantly brighter, then it is identified asnighttime condition and the LED will remain ON; otherwise, it isidentified as daytime condition and the LED can remain OFF.

Step-2 image preprocessing performs such activities as removing randomnoise and enhancing contrast. Under daylight condition, the imagecontains unwanted contents because the background is illuminated bysunlight. For example, the movement of the driver, other passengers inthe backseat, and the scenes outside the passenger window can interfereif they are visible in the image. Usually, these unwanted contentscannot be completely eliminated by adjusting the camera position, butthey can be removed by image preprocessing. This process is much lesscomplicated for some vehicle monitoring cases such as trailer and cargocontainers where sunlight is rarely a problem.

Step-3 feature extraction compresses the data from, for example, the76,800 image pixels in the prototype camera to only a few hundredfloating-point numbers, which may be based of edge detection algorithms,while retaining most of the important information. In this step, theamount of the data is significantly reduced so that it becomes possibleto process the data using neural networks in Step-4.

There are many methods to extract information from an image for thepurposes herein. One preferred method is to extract information as tothe location of the edges of an object and then to input thisinformation into a pattern recognition algorithm. As will be discussedbelow, the location and use of the edges of an occupying item asfeatures in an imager is an important contribution of the inventionsdisclosed herein for occupant or other object sensing and tracking in avehicle.

Steps 2 and 3, image pre-processing and feature extraction can becombined or both performed separately by use of one or more of the imagesubtraction techniques described herein. One image subtraction techniqueis to compare a later obtained image from a series of images from animager to at least one previously obtained image from the series ofimages from the same imager to ascertain the presence of differencesbetween the images. Step 4, below, is the analysis of the differences toobtain information about the occupying item. There are various ways tocompare images, one of which is to subtract the later obtained imagefrom the previously obtained image to determine which image pixels havechanged in value. In one embodiment, the previously obtained image isobtained without infrared illumination and the later obtained image isobtained with infrared illumination. Comparison of the images can thusinvolve subtracting the later obtained image from the previouslyobtained image or subtracting the previously obtained image from thelater obtained image. The images may be obtained from a single imagingdevice mounted in the vehicle to obtain the entire series of images. Insome embodiments, each previously obtained image is an image of thecompartment including permanent structure in the compartment without atemporary occupying item. Comparison of images may thus involvesubtracting each previously obtained image from the later obtained imageto thereby remove the effect of the presence of permanent structure fromthe later obtained image. In one embodiment, edges of shapes in theimages are determined prior to comparison of the images such that onlythe determined edges of the shapes of the previously obtained image andthe later obtained image are compared to one another. Comparison ofimages may involve determining which reflections of the occupying itemremain static for all of the images and determining which reflectionsmove between the images whereby analysis of the differences constitutesanalyzing the reflections which move.

Step-4, to increase the system learning capability and performancestability, modular or combination neural networks can be used with eachmodule handling a different subtask (for example, to handle eitherdaytime or nighttime condition, or to classify a specific occupantgroup). In an optical embodiment for analysis of an occupying item in aseat, after use of image subtraction techniques to images, differencesbetween the images may be analyzed using a neural network or moregenerally any trained pattern recognition system, to determine, forexample, position of the occupying item such as the position relative toan occupant protection system, to determine the presence of a head orchest of a human occupant if a human is the occupying item and theposition of the head or chest, when present, relative to a deployableoccupant protection system, to determine motion of the occupying itemand to determine an identity of the occupying item. As a result of theanalysis, deployment of the occupant protection system can becontrolled, e.g., based on the position of the head or chest of theoccupant when the presence of an occupant is determined.

Step-5 post-processing removes random noise in the neural networkoutputs via filtering. Besides filtering, additional knowledge can beused to remove some of the undesired changes in the neural networkoutput. For example, it is impossible to change from an adult passengerto a child restraint without going through an empty-seat state orkey-off. After post-processing, the final decision of classification isoutput to the airbag control module, or other system, and it is up tothe automakers or vehicle owners or managers to decide how to utilizethe information. A set of display LED's on the instrument panel providesthe same information to the vehicle occupant(s).

If multiple images are acquired substantially simultaneously, each by adifferent image acquisition device, then each image can be processed inthe manner above. A comparison of the classification of the occupantobtained from the processing of the image obtained by each imageacquisition device can be performed to ascertain any variations. Ifthere are no variations, then the classification of the occupant islikely to be very accurate. However, in the presence of variations, thenthe images can be discarded and new images acquired until variations areeliminated.

A majority approach might also be used. For example, if three or moreimages are acquired by three different cameras, or other imagers, thenif two provide the same classification, this classification will beconsidered the correct classification. Alternately, all of the data fromall of the images can be analyzed and together in one combined neuralnetwork or combination neural network.

Referring again to FIG. 21, after the occupant is classified from theacquired image or images, i.e., as an empty seat (classification 1), aninfant carrier or an occupied rearward-facing child seat (classification2), a child or occupied forward-facing child seat (classification 3) oran adult passenger (classification 4), additional classification may beperformed for the purpose of determining a recommendation for control ofa vehicular component such as an occupant restraint device.

For classifications 1 and 2, the recommendation is always to suppressdeployment of the occupant restraint device. For classifications 3 and4, dynamic position tracking is performed. This involves the training ofneural networks or other pattern recognition techniques, one for eachclassification, so that once the occupant is classified, the particularneural network can be trained to analyze the dynamic position of thatoccupant will be used. That is, the data from acquired images will beinput to the neural network to determine a recommendation for control ofthe occupant restraint device and also into the neural network fordynamic position tracking of an adult passenger when the occupant isclassified as an adult passenger. The recommendation may be either asuppression of deployment, a depowered deployment or a full powerdeployment.

To additionally summarize, the system described can be a single ormultiple camera or other imager system where the cameras are typicallymounted on the roof or headliner of the vehicle either on the roof railsor center or other appropriate location. The source of illumination istypically one or more infrared LEDs and if infrared, the images aretypically monochromic, although color can effectively be used whennatural illumination is available. Images can be obtained at least asfast as 100 frames per second; however, slower rates are frequentlyadequate. A pattern recognition algorithmic system can be used toclassify the occupancy of a seat into a variety of classes such as: (1)an empty seat; (2) an infant seat which can be further classified asrear or forward facing; (3) a child which can be further classified asin or out-of-position and (4) an adult which can also be furtherclassified as in or out-of-position. Such a system can be used tosuppress the deployment of an occupant restraint. If the occupant isfurther tracked so that his or her position relative to the airbag, forexample, is known more accurately, then the airbag deployment can betailored to the position of the occupant. Such tracking can beaccomplished since the location of the head of the occupant is eitherknown from the analysis or can be inferred due to the position of otherbody parts.

Data and images from the occupant sensing system, which can include anassessment of the type and magnitude of injuries, along with locationinformation if available, can be sent to an appropriate off-vehiclelocation such as an emergency medical system (EMS) receiver eitherdirectly by cell phone, for example, via a telematics system such asOnStar®, or over the internet if available in order to aid the servicein providing medical assistance and to access the urgency of thesituation. The system can additionally be used to identify that thereare occupants in the vehicle that has been parked, for example, and tostart the vehicle engine and heater if the temperature drops below asafe threshold or to open a window or operate the air conditioning inthe event that the temperature raises to a temperature above a safethreshold. In both cases, a message can be sent to the EMS or otherservices by any appropriate method such as those listed above. A messagecan also be sent to the owner's beeper or PDA.

The system can also be used alone or to augment the vehicle securitysystem to alert the owner or other person or remote site that thevehicle security has been breeched so as to prevent danger to areturning owner or to prevent a theft or other criminal act. Asdiscussed herein, one method of alerting the owner or another interestedperson is through a satellite communication with a service such asSkybitz or equivalent. The advantage here is that the power required tooperate the system can be supplied by a long life battery and thus thesystem can be independent of the vehicle power system.

As discussed above and below, other occupant sensing systems can also beprovided that monitor the breathing or other motion of the driver, forexample, including the driver's heartbeat, eye blink rate, gestures,direction or gaze and provide appropriate responses including thecontrol of a vehicle component including any such components listedherein. If the driver is falling asleep, for example, a warning can beissued and eventually the vehicle directed off the road if necessary.

The combination of a camera system with a microphone and speaker allowsfor a wide variety of options for the control of vehicle components. Asophisticated algorithm can interpret a gesture, for example, that maybe in response to a question from the computer system. The driver mayindicate by a gesture that he or she wants the temperature to change andthe system can then interpret a “thumbs up” gesture for highertemperature and a “thumbs down” gesture for a lower temperature. When itis correct, the driver can signal by gesture that it is fine. A verylarge number of component control options exist that can be entirelyexecuted by the combination of voice, speakers and a camera that can seegestures. When the system does not understand, it can ask to have thegesture repeated, for example, or it can ask for a confirmation. Note,the presence of an occupant in a seat can even be confirmed by a wordspoken by the occupant, for example, which can use a technology known asvoice print if it is desired to identify the particular occupant.

It is also to be noted that the system can be trained to recognizeessentially any object or object location that a human can recognize andeven some that a human cannot recognize since the system can have thebenefit of special illumination as discussed above. If desired, aparticular situation such as the presence of a passenger's feet on theinstrument panel, hand on a window frame, head against the side window,or even lying down with his or her head in the lap of the driver, forexample, can be recognized and appropriate adjustments to a componentperformed.

Note, it has been assumed that the camera would be permanently mountedin the vehicle in the above discussion. This need not be the case andespecially for some after-market products, the camera function can besupplied by a cell phone or other device and a holder appropriately (andremovably) mounted in the vehicle.

Again the discussion above related primarily to sensing the interior ofand automotive vehicle for the purposes of controlling a vehiclecomponent such as a restraint system. When the vehicle is a shippingcontainer then different classifications can be used depending on theobjective. If it is to determine whether there is a life form movingwithin the container, a stowaway, for example, then that can be oneclassification. Another may be the size of a cargo box or whether it ismoving. Still another may be whether there is an unauthorized entry inprogress or that the door has been opened. Others include the presenceof a particular chemical vapor, radiation, excessive temperature,excessive humidity, excessive shock, excessive vibration etc.

1.2.1 Eyesafe Application

When using optics, the use of eye-safe frequencies is critical if thereis a possibility that a human occupant is in the scanning field.Currently, active IR uses the near IR range which has wavelengths below1400 nanometers. Recent developments in the SWIR range (particularlygreater than 1400 nm and more specifically in a range of 1400 nm toabout 1700 nm) use indium gallium arsenide (InGaAs) for an imager permitmuch higher power transmissions as they are below the eye safety zone(see, e.g., Martin H. Ettenberg “A Little Night Vision”, Solutions forthe Electronic Imaging Professional, March 2005, a Cygnus Publication).

Use of such eyesafe IR, i.e., greater than 1400 nm, to artificiallyilluminate an area being observed is significantly advantageous sincemuch brighter illumination can be used. If images are taken in such anartificially illuminated area with a camera that is only sensitive inthis range, through use of appropriate notch filter, then the effects ofsunlight and other artificial light can be removed. This makes thesystem much less sensitive to sunlight effects. It also makes the systemeasier to record an image (or an edge image) of an empty seat, forexample, that would be invariant to sun or other uncontrollableillumination and thus the system would be more robust. The edges of aseat, for example, would always look the same regardless of the externalillumination.

Use of a near infrared frequency such as SWIR (above 1.4 microns) may bein the form of a laser spotlight which would pass eye safetyrequirements. This laser spotlight coupled with range gating, e.g.,through use of a notch filter, permits easy segmentation of objects inthe captured image and thus the rapid classification using, for example,a modular neural network or combination neural network system.

Application of artificial illumination in a frequency above 1400 nm canbe implemented in any of the embodiments described herein whereinillumination is or can be provided to the vehicular compartment withimages thereof being obtained subsequent to or contemporaneous with theillumination. Obtaining images in the presence of artificialillumination and in the absence of such illumination enables asubtraction of the images obtained during the illumination from thoseobtained without illumination with the resultant images beingprocessable to determine information about any objects in the images,including for example, the presence of absence of such objects.

1.3 Ultrasonics and Optics

In some cases, a combination of an optical system such as a camera andan ultrasonic system can be used. In this case, the optical system canbe used to acquire an image providing information as to the vertical andlateral dimensions of the scene and the ultrasound can be used toprovide longitudinal information, for example.

A more accurate acoustic system for determining the distance to aparticular object, or a part thereof, in the passenger compartment isexemplified by transducers 24 in FIG. 5E. In this case, three ultrasonictransmitter/receivers 24 are shown spaced apart mounted onto theA-pillar of the vehicle. Due to the wavelength, it is difficult to get anarrow beam using ultrasonics without either using high frequencies thathave limited range or a large transducer. A commonly available 40 kHztransducer, for example, is about 1 cm. in diameter and emits a sonicwave that spreads at about a sixty-degree angle. To reduce this anglerequires making the transducer larger in diameter. An alternate solutionis to use several transducers and to phase the transmissions from thetransducers so that they arrive at the intended part of the target inphase. Reflections from the selected part of the target are thenreinforced whereas reflections from adjacent parts encounterinterference with the result that the distance to the brightest portionwithin the vicinity of interest can be determined. A low-Q transducermay be necessary for this application.

By varying the phase of transmission from the three transducers 24, thelocation of a reflection source on a curved line can be determined. Inorder to locate the reflection source in space, at least one additionaltransmitter/receiver is required which is not co-linear with the others.The waves shown in FIG. 5E coming from the three transducers 24 areactually only the portions of the waves which arrive at the desiredpoint in space together in phase. The effective direction of these wavestreams can be varied by changing the transmission phase between thethree transmitters 24.

A determination of the approximate location of a point of interest onthe occupant can be accomplished by a CCD or CMOS array and appropriateanalysis and the phasing of the ultrasonic transmitters is determined sothat the distance to the desired point can be determined.

Although the combination of ultrasonics and optics has been described,it will now be obvious to others skilled in the art that other sensortypes can be combined with either optical or ultrasonic transducersincluding weight sensors of all types as discussed below, as well aselectric field, chemical, temperature, humidity, radiation, vibration,acceleration, velocity, position, proximity, capacitance, angular rate,heartbeat, radar, other electromagnetic, and other sensors.

1.4 Other Transducers

In FIG. 4, the ultrasonic transducers of the previous designs can bereplaced by laser or other electromagnetic wave transducers ortransceivers 8 and 9, which are connected to a microprocessor 20. Asdiscussed above, these are only illustrative mounting locations and anyof the locations described herein are suitable for particulartechnologies. Also, such electromagnetic transceivers are meant toinclude the entire electromagnetic spectrum including from X-rays to lowfrequencies where sensors such as capacitive or electric field sensorsincluding so called “displacement current sensors”, and the auto-tuneantenna sensor also discussed herein operate.

A block diagram of an antenna based near field object detector isillustrated in FIG. 23. The circuit variables are defined as follows:

F=Frequency of operation Hz.

ω=2*π*F radians/second

α=Phase angle between antenna voltage and antenna current.

A, k1, k2, k3, k4 are scale factors, determined by system design.

Tp1-8 are points on FIG. 16.

Tp1=k1*Sin(ωt)

Tp2=k1*Cos(ωt) Reference voltage to phase detector

Tp3=k2*Sin(ωt) drive voltage to Antenna

Tp4=k3*Cos(ωt+δ) Antenna current

Tp5=k4*Cos(ωt+δ) Voltage representing Antenna current

Tp6=0.5ωt)Sin(ωT) Output of phase detector

Tp7=Absorption signal output

Tp8=Proximity signal output

In a tuned circuit, the voltage and the current are 90 degrees out ofphase with each other at the resonant frequency. The frequency sourcesupplies a signal to the phase shifter. The phase shifter outputs twosignals that are out of phase by 90 degrees at frequency F. The drive tothe antenna is the signal Tp3. The antenna can be of any suitable typesuch as dipole, patch, Yagi etc. When the signal Tp1 from the phaseshifter has sufficient power, the power amplifier may be eliminated. Theantenna current is at Tp4, which is converted into a voltage since thephase detector requires a voltage drive. The output of the phasedetector is Tp6, which is filtered and used to drive the varactor tuningdiode D1. Multiple diodes may be used in place of diode D1. The phasedetector, amplifier filter, varactor tuning diode D1 and current tovoltage converter form a closed loop servo that keeps the antennavoltage and current in a 90-degree relationship at frequency F. Thetuning loop maintains a 90-degree phase relationship between the antennavoltage and the antenna current. When an object such as a human comesnear the antenna and attempts to detune it, the phase detector sensesthe phase change and adds or subtracts capacity by changing voltage tothe varactor tuning diode D1 thereby maintaining resonance at frequencyF.

The voltage Tp8 is an indication of the capacity of a nearby object. Anobject that is near the loop and absorbs energy from it, will change theamplitude of the signal at Tp5, which is detected and outputted to Tp7.The two signals Tp7 and Tp8 are used to determine the nature of theobject near the antenna.

An object such as a human or animal with a fairly high electricalpermittivity or dielectric constant and a relatively high lossdielectric property (high loss tangent) absorbs significant energy. Thiseffect varies with the frequency used for the detection. If a human, whohas a high loss tangent is present in the detection field, then thedielectric absorption causes the value of the capacitance of the objectto change with frequency. For a human with high dielectric losses (highloss tangent), the decay with frequency will be more pronounced than forobjects that do not present this high loss tangency. Exploiting thisphenomenon makes it possible to detect the presence of an adult, child,baby, pet or other animal in the detection field.

An older method of antenna tuning used the antenna current and thevoltage across the antenna to supply the inputs to a phase detector. Ina 25 to 50 mw transmitter with a 50 ohm impedance, the current is small,it is therefore preferable to use the method described herein.

Note that the auto-tuned antenna sensor is preferably placed in thevehicle seat, headrest, floor, dashboard, headliner, or airbag modulecover for an automotive vehicle. Seat mounted examples are shown at 12,13, 14 and 15 in FIG. 4 and a floor mounted example at 11. In most othermanners, the system operates the same. The geometry of the antennasystem would differ depending on the vehicle to which it is applied andthe intended purpose. Such a system, for example, can be designed todetect the entry of a person into a container or trailer through thedoor.

1.5 Circuits

There are several preferred methods of implementing the vehicle interiormonitoring systems of at least one of the inventions disclosed hereinincluding a microprocessor, an application specific integrated circuitsystem (ASIC), a system on a chip and/or an FPGA or DSP. These systemsare represented schematically as 20 herein. In some systems, both amicroprocessor and an ASIC are used. In other systems, most if not allof the circuitry is combined onto a single chip (system on a chip). Theparticular implementation depends on the quantity to be made andeconomic considerations. It also depends on time-to-marketconsiderations where FPGA is frequently the technology of choice.

The design of the electronic circuits for a laser system is described inU.S. Pat. No. 5,653,462 and in particular FIG. 8 thereof and thecorresponding description.

2. Adaptation

The process of adapting a system of occupant or object sensingtransducers to a vehicle is described in the '996 application, section2.

Referring again to FIG. 6, motion sensor 73 can be a discrete sensorthat detects relative motion in the passenger compartment of thevehicle. Such sensors are frequently based on ultrasonics and canmeasure a change in the ultrasonic pattern that occurs over a short timeperiod. Alternately, the subtracting of one position vector from aprevious position vector to achieve a differential position vector candetect motion. For the purposes herein, a motion sensor will be used tomean either a particular device that is designed to detect motion forthe creation of a special vector based on vector differences or a neuralnetwork trained to determine motion based on successive vectors.

An ultrasonic, optical or other sensor or transducer system 9 can bemounted on the upper portion of the front pillar, i.e., the A-Pillar, ofthe vehicle and a similar sensor system 6 can be mounted on the upperportion of the intermediate pillar, i.e., the B-Pillar. Each sensorsystem 6, 9 may comprise a transducer. The outputs of the sensor systems6 and 9 can be input to a band pass filter 60 through a multiplexcircuit 59 which can be switched in synchronization with a timing signalfrom the ultrasonic sensor drive circuit 58, for example, and then canbe amplified by an amplifier 61. The band pass filter 60 removes a lowfrequency wave component from the output signal and also removes some ofthe noise. The envelope wave signal can be input to an analog/digitalconverter (ADC) 62 and digitized as measured data. The measured data canbe input to a processing circuit 63, which can be controlled by thetiming signal which can be in turn output from the sensor drive circuit58. The above description applies primarily to systems based onultrasonics and will differ somewhat for optical, electric field andother systems and for different vehicle types.

Each of the measured data can be input to a normalization circuit 64 andnormalized. The normalized measured data can be input to the combinationneural network (circuit) 65, for example, as wave data.

The output of the pressure or weight sensor(s) 7, 76 can be amplified byan amplifier 66 coupled to the pressure or weight sensor(s) 7, 76 andthe amplified output can be input to an analog/digital converter andthen directed to the neural network 65, for example, of the processor.Amplifier 66 can be useful in some embodiments but it may be dispensedwith by constructing the sensors 7, 76 to provide a sufficiently strongoutput signal, and even possibly a digital signal. One manner to do thiswould be to construct the sensor systems with appropriate electronics.

The neural network 65 can be directly connected to the ADCs 68 and 69,the ADC associated with amplifier 66 and the normalization circuit 64.As such, information from each of the sensors in the system (a stream ofdata) can be passed directly to the neural network 65 for processingthereby. The streams of data from the sensors are usually not combinedprior to the neural network 65 and the neural network 65 can be designedto accept the separate streams of data (e.g., at least a part of thedata at each input node) and process them to provide an outputindicative of the current occupancy state of the seat or of the vehicle.The neural network 65 thus includes or incorporates a plurality ofalgorithms derived by training in the manners discussed herein. Once thecurrent occupancy state of the seat or vehicle is determined, it ispossible to control vehicular components or systems, such as the airbagsystem or telematics system, in consideration of the current occupancystate of the seat or vehicle.

A discussion of the methodology of adapting a monitoring system to anautomotive vehicle for the purpose primarily of controlling a componentsuch as a restraint system is described with reference to FIGS. 28-37 ofthe '934 application.

3. Mounting Locations for and Quantity of Transducers

Ultrasonic transducers are relatively good at measuring the distancealong a radius to a reflective object. An optical array, to be discussednow, on the other hand, can get accurate measurements in two dimensions,the lateral and vertical dimensions relative to the transducer. Assumingthe optical array has dimensions of 100 by 100 as compared to anultrasonic sensor that has a single dimension of 100, an optical arraycan therefore provide 100 times more information than the ultrasonicsensor. Most importantly, this vastly greater amount of information doesnot cost significantly more to obtain than the information from theultrasonic sensor.

As illustrated in FIGS. 8A-8D, the optical sensors are typically locatedfor an automotive vehicle at the positions where the desired informationis available with the greatest resolution. These positions are typicallyin the center front and center rear of the occupancy seat and at thecenter on each side and top. This is in contrast to the optimum locationfor ultrasonic sensors, which are the corners of such a rectangle thatoutlines the seated volume. Styling and other constraints often preventmounting of transducers at the optimum locations.

An optical infrared transmitter and receiver assembly is shown generallyat 52 in FIG. 8B and is mounted onto the instrument panel facing thewindshield. Assembly 52 can either be recessed below the upper face ofthe instrument panel or mounted onto the upper face of the instrumentpanel. Assembly 52, shown enlarged, comprises a source of infraredradiation, or another form of electromagnetic radiation, and a CCD, CMOSor other appropriate arrays of typically 160 pixels by 160 pixels. Inthis embodiment, the windshield is used to reflect the illuminationlight provided by the infrared radiation toward the objects in thepassenger compartment and also reflect the light being reflected back bythe objects in the passenger compartment, in a manner similar to the“heads-up” display which is now being offered on several automobilemodels. The “heads-up” display, of course, is currently used only todisplay information to the driver and is not used to reflect light fromthe driver to a receiver. Once again, unless one of the distancemeasuring systems as described below is used, this system alone cannotbe used to determine distances from the objects to the sensor. Its mainpurpose is object identification and monitoring. Depending on theapplication, separate systems can be used for the driver and for thepassenger. In some cases, the cameras located in the instrument panelwhich receive light reflected off of the windshield can be co-locatedwith multiple lenses whereby the respective lenses aimed at the driverand passenger seats respectively.

Assembly 52 is actually about two centimeters or less in diameter and isshown greatly enlarged in FIG. 8B. Also, the reflection area on thewindshield is considerably smaller than illustrated and specialprovisions are made to assure that this area of the windshield is flatand reflective as is done generally when heads-up displays are used. Forcases where there is some curvature in the windshield, it can be atleast partially compensated for by the CCD optics.

Transducers 23-25 are illustrated mounted onto the A-pillar of thevehicle, however, since these transducers are quite small, typicallyless than 2 cm on a side, they could alternately be mounted onto thewindshield itself, or other convenient location which provides a clearview of the portion of the passenger compartment being monitored. Otherpreferred mounting locations include the headliner above and also theside of the seat. Some imagers are now being made that are less than 1cm on a side.

FIG. 24 is a side view, with certain portions removed or cut away, of aportion of the passenger compartment of a vehicle showing preferredmounting locations of optical interior vehicle monitoring sensors(transmitter/receiver assemblies or transducers) 49, 50, 51, 54, 126,127, 128, 129, and 130. Each of these sensors is illustrated as having alens and is shown enlarged in size for clarity. In a typical actualdevice, the diameter of the lens is less than 2 cm and it protrudes fromthe mounting surface by less than 1 cm. Specially designed sensors canbe considerably smaller. This small size renders these devices almostunnoticeable by vehicle occupants. Since these sensors are optical, itis important that the lens surface remains relatively clean. Controlcircuitry 132, which is coupled to each transducer, contains aself-diagnostic feature where the image returned by a transducer iscompared with a stored image and the existence of certain key featuresis verified. If a receiver fails this test, a warning is displayed tothe driver which indicates that cleaning of the lens surface isrequired.

The technology illustrated in FIG. 24 can be used for numerous purposesrelating to monitoring of the space in the passenger compartment behindthe driver including: (i) the determination of the presence and positionof objects in the rear seat(s), (ii) the determination of the presence,position and orientation of child seats 2 in the rear seat, (iii) themonitoring of the rear of an occupant's head 33, (iv) the monitoring ofthe position of occupant 30, (v) the monitoring of the position of theoccupant's knees 35, (vi) the monitoring of the occupant's positionrelative to the airbag 44, (vii) the measurement of the occupant'sheight, as well as other monitoring functions as described herein.

Information relating to the space behind the driver can be obtained byprocessing the data obtained by the sensors 126, 127, 128 and 129, whichdata would be in the form of images if optical sensors are used as inthe preferred embodiment. Such information can be the presence of aparticular occupying item or occupant, e.g., a rear facing child seat 2as shown in FIG. 24, as well as the location or position of occupyingitems. Additional information obtained by the optical sensors caninclude an identification of the occupying item. The informationobtained by the control circuitry by processing the information fromsensors 126, 127, 128 and 129 may be used to affect any other system orcomponent in the vehicle in a similar manner as the information from thesensors which monitor the front seat is used as described herein, suchas the airbag system. Processing of the images obtained by the sensorsto determine the presence, position and/or identification of anyoccupants or occupying item can be effected using a pattern recognitionalgorithm in any of the ways discussed herein, e.g., a trained neuralnetwork. For example, such processing can result in affecting acomponent or system in the front seat such as a display that allows theoperator to monitor what is happening in the rear seat without having toturn his or her head.

In the preferred implementation, as shown in FIGS. 8A-8E, fourtransducer assemblies are positioned around the seat to be monitored,each can comprise one or more LEDs with a diverging lenses and a CMOSarray. Although illustrated together, the illuminating source in manycases will not be co-located with the receiving array. The LED emits acontrolled angle, 120° for example, diverging cone of infrared radiationthat illuminates the occupant from both sides and from the front andrear. This angle is not to be confused with the field angle used inultrasonic systems. With ultrasound, extreme care is required to controlthe field of the ultrasonic waves so that they will not create multipatheffects and add noise to the system. With infrared, there is no reason,in the implementation now being described, other than to make the mostefficient use of the infrared energy, why the entire vehicle cannot beflooded with infrared energy either from many small sources or from afew bright ones.

The image from each array is used to capture two dimensions of occupantposition information, thus, the array of assembly 50 positioned on thewindshield header, which is approximately 25% of the way laterallyacross the headliner in front of the driver, provides a both verticaland transverse information on the location of the driver. A similar viewfrom the rear is obtained from the array of assembly 54 positionedbehind the driver on the roof of the vehicle and above the seatbackportion of the seat 72. As such, assembly 54 also provides both verticaland transverse information on the location of the driver. Finally,arrays of assemblies 49 and 51 provide both vertical and longitudinaldriver location information. Another preferred location is the headlinercentered directly above the seat of interest. The position of theassemblies 49-52 and 54 may differ from that shown in the drawings. Inthe invention, in order that the information from two or more of theassemblies 49-52 and 54 may provide a three-dimensional image of theoccupant, or portion of the passenger compartment, the assembliesgenerally should not be arranged side-by-side. A side-by-sidearrangement will provide two essentially identical views with thedifference being a lateral shift. This does not enable a completethree-dimensional view of the occupant.

One important point concerns the location and number of opticalassemblies. It is possible to use fewer than four such assemblies with apossible resulting loss in accuracy. The number of four was chosen sothat either a forward or rear assembly or either of the side assembliescan be blocked by a newspaper, for example, without seriously degradingthe performance of the system. Since drivers rarely are readingnewspapers while driving, fewer than four arrays are usually adequatefor the driver side. In fact, one is frequently sufficient. One camerais also usually sufficient for the passenger side if the goal of thesystem is classification only or if camera blockage is tolerated foroccupant tracking.

The particular locations of the optical assemblies were chosen to givethe most accurate information as to the locations of the occupant. Thisis based on an understanding of what information can be best obtainedfrom a visual image. There is a natural tendency on the part of humansto try to gauge distance from the optical sensors directly. This is atbest complicated involving focusing systems, stereographic systems,multiple arrays and triangulation, time of flight measurement, etc. Whatis not intuitive to humans is to not try to obtain this distancedirectly from apparatus or techniques associated with the mountinglocation. Whereas ultrasound is quite good for measuring distances fromthe transducer (the z-axis), optical systems are better at measuringdistances in the vertical and lateral directions (the x and y-axes).Since the precise locations of the optical transducers are known, thatis, the geometry of the transducer locations is known relative to thevehicle, there is no need to try to determine the displacement of anobject of interest from the transducer (the z-axis) directly. This canmore easily be done indirectly by another transducer. That is, thevehicle z-axis to one transducer is the camera x-axis to another.

Another preferred location of a transmitter/receiver for use withairbags is shown at 54 in FIG. 5. In this case, the device is attachedto the steering wheel and gives an accurate determination of thedistance of the driver's chest from the airbag module. Thisimplementation would generally be used with another device such as 50 atanother location. Additional details about mounting of a transducer on acover of an airbag module are found in section 3 of the '996 applicationwith reference to FIG. 13 therein, incorporated by reference herein.

One problem of the system using a transmitter/receiver 54 in FIG. 5 isthat a driver may have inadvertently placed his hand over thetransmitter/receiver 54, thus defeating the operation of the device. Asecond confirming transmitter/receiver 50 can therefore be placed atsome other convenient position such as on the roof or headliner of thepassenger compartment as shown in FIG. 5. This transmitter/receiver 50operates in a manner similar to transmitter/receiver 54.

The applications described herein have been illustrated using the driverof the vehicle. The same systems of determining the position of theoccupant relative to the airbag apply to the passenger, sometimesrequiring minor modifications. Also of course, a similar system can beappropriately designed for other monitoring situations such as for cargocontainers and truck trailers.

It is likely that the sensor required triggering time based on theposition of the occupant will be different for the driver than for thepassenger. Current systems are based primarily on the driver with theresult that the probability of injury to the passenger is necessarilyincreased either by deploying the airbag too late or by failing todeploy the airbag when the position of the driver would not warrant itbut the passenger's position would. With the use of occupant positionsensors for both the passenger and driver, the airbag system can beindividually optimized for each occupant and result in furthersignificant injury reduction. In particular, either the driver orpassenger system can be disabled if either the driver or passenger isout of position.

There is almost always a driver present in vehicles that are involved inaccidents where an airbag is needed. Only about 30% of these vehicles,however, have a passenger. If the passenger is not present, there isusually no need to deploy the passenger side airbag. The occupantposition sensor, when used for the passenger side with proper patternrecognition circuitry, can also ascertain whether or not the seat isoccupied, and if not, can disable the deployment of the passenger sideairbag and thereby save the cost of its replacement. A sophisticatedpattern recognition system could even distinguish between an occupantand a bag of groceries or a box, for example, which in some cargocontainer or truck trailer monitoring situations is desired. Finally,there has been much written about the out of position child who isstanding or otherwise positioned adjacent to the airbag, perhaps due topre-crash braking. The occupant position sensor described herein canprevent the deployment of the airbag in this situation.

3.1 Single Camera, Dual Camera with Single Light Source

Many automobile companies are opting to satisfy the requirements ofFMVSS-208 by using a weight only system such as the bladder or straingage systems disclosed here. Such a system provides an elementarymeasure of the weight of the occupying object but does not give areliable indication of its position, at least for automotive vehicles.It can also be easily confused by any object that weighs 60 or morepounds and that is interpreted as an adult. Weight only systems are alsostatic systems in that due to vehicle dynamics that frequently accompanya pre crash braking event they are unable to track the position of theoccupant. The load from seatbelts can confuse the system and therefore aspecial additional sensor must be used to measure seatbelt tension. Insome systems, the device must be calibrated for each vehicle and thereis some concern as to whether this calibration will be proper for thelife on the vehicle.

A single camera can frequently provide considerably more informationthan a weight only system without the disadvantages of weight sensorsand do so at a similar cost. Such a single camera in its simplestinstallation can categorize the occupancy state of the vehicle anddetermine whether the airbag should be suppressed due to an empty seator the presence of a child of a size that corresponds to one weighingless than 60 pounds. Of course, a single camera can also easily doconsiderably more by providing a static out-of-position indication and,with the incorporation of a faster processor, dynamic out-of-positiondetermination can also be provided. Thus, especially with the costs ofmicroprocessors continuing to drop, a single camera system can easilyprovide considerably more functionality than a weight only system andyet stay in the same price range.

A principal drawback of a single camera system is that it can be blockedby the hand of an occupant or by a newspaper, for example. This is arare event since the preferred mounting location for the camera istypically high in the vehicle such as on the headliner. Also, it isconsiderably less likely that the occupant will always be reading anewspaper, for example, and if he or she is not reading it when thesystem is first started up, or at any other time during the trip, thecamera system will still get an opportunity to see the occupant when heor she is not being blocked and make the proper categorization. Theability of the system to track the occupant will be impaired but thesystem can assume that the occupant has not moved toward the airbagwhile reading the newspaper and thus the initial position of theoccupant can be retained and used for suppression determination.Finally, the fact that the camera is blocked can be determined and thedriver made aware of this fact in much the same manner that a seatbeltlight notifies the driver that the passenger is not wearing his or herseatbelt.

The accuracy of a single camera system can be above 99% whichsignificantly exceeds the accuracy of weight only systems. Nevertheless,some automobile manufacturers desire even greater accuracy and thereforeopt for the addition of a second camera. Such a camera is usually placedon the opposite side of the occupant as the first camera. The firstcamera may be placed on or near the dome light, for example, and thesecond camera can be on the headliner above the side door. A dual camerasystem such as this can operate more accurately in bright daylightsituations where the window area needs to be ignored in the view of thecamera that is mounted near the dome.

Sometimes, in a dual camera system, only a single light source is used.This provides a known shadow pattern for the second camera and helps toaccentuate the edges of the occupying item rendering classificationeasier. Any of the forms of structured light can also be used andthrough these and other techniques the corresponding points in the twoimages can more easily be determined thus providing a three-dimensionalmodel of the occupant or occupying object in the case of other vehicletypes such as a cargo container or truck trailer.

As a result, the current assignee has developed a low cost single camerasystem which has been extensively tested for the most difficult problemof automobile occupant sensing but is nevertheless also applicable formonitoring of other vehicles such as cargo containers and trucktrailers. The automotive occupant position sensor system uses a CMOScamera in conjunction with pattern recognition algorithms for thediscrimination of out-of-position occupants and rear facing child safetyseats. A single imager, located strategically within the occupantcompartment, is coupled with an infrared LED that emits unfocused,wide-beam pulses toward the passenger volume. These pulses, whichreflect off of objects in the passenger seat and are captured by thecamera, contain information for classification and locationdetermination in approximately 10 msec. The decision algorithm processesthe returned information using a uniquely trained neural network, whichmay not be necessary in the simpler cargo container or truck trailermonitoring cases. The logic of the neural network was developed throughextensive in-vehicle training with thousands of realistic occupant sizeand position scenarios. Although the optical occupant position sensorcan be used in conjunction with other technologies (such as weightsensing, seat belt sensing, crash severity sensing, etc.), it is astand-alone system meeting the requirements of FMVSS-208. This devicewill be discussed below.

3.2 Location of the Transducers

Any of the transducers discussed herein such as an active pixel or othercamera can be arranged in various locations in the vehicle including ina headliner, roof, ceiling, rear view mirror assembly, an A-pillar, aB-pillar and a C-pillar or a side wall or even a door in the case of acargo container or truck trailer. Images of the front seat area or therear seat area can be obtained by proper placement and orientation ofthe transducers such as cameras. The rear view mirror assembly can be agood location for a camera, particularly if it is attached to theportion of the mirror support that does not move when the occupant isadjusting the mirror. Cameras at this location can get a good view ofthe driver, passenger as well as the environment surrounding the vehicleand particularly in the front of the vehicle. It is an ideal locationfor automatic dimming headlight cameras.

3.3 Color Cameras—Multispectral Imaging

Most if not all occupant sensing systems, except those of the currentassignee, developed to date as reported in the patent and non-patentliterature have been generally based on a single frequency. As discussedherein, use of multiple frequencies with ultrasound makes it possible tochange a static system into a dynamic system allowing the occupant to betracked during pre-crash braking, for example. Multispectral imaging canalso provide advantages for camera or other optical-based systems. Thecolor of the skin of an occupant is a reliable measure of the presenceof an occupant and also renders the segmentation of the image to be moreeasily accomplished. Thus, the face can be more easily separated fromthe rest of the image simplifying the determination of the location ofthe eyes of the driver, for example. This is particularly true forvarious frequencies of passive and active infrared. Also, as discussedbelow, life forms react to radiation of different frequenciesdifferently than non-life forms again making the determination of thepresence of a life form easier. Finally, there is just considerably moreinformation in a color or multispectral image than in a monochromicimage. This additional information improves the accuracy of theidentification and tracking process and thus of the system. In manycases, this accuracy improvement is so small that the added cost is notjustified but as costs of electronics and cameras continue to drop thisequation is changing and it is expected that multispectral imaging willprevail.

Illumination for nighttime is frequently done using infrared. Whenmultispectral imaging is used the designer has the choice of revertingto IR only for night time or using a multispectral LED and a verysensitive camera so that the flickering light does not annoy the driver.Alternately, a sensitive camera along with a continuous low level ofillumination can be used. Of course, multispectral imaging does notrequire that the visible part of the spectrum be used. Ultraviolet,X-rays and many other frequencies in the infrared part of the spectrumare available. Life forms, particularly humans, exhibit particularlyinteresting and identifiable reactions (reflection, absorption,scattering, transmission, emission) to frequencies in other parts of theelectromagnetic spectrum (see for example the book Alien Visionreferenced above) as discussed herein.

3.4 High Dynamic Range Cameras

An active pixel camera is a special camera which has the ability toadjust the sensitivity of each pixel of the camera similar to the mannerin which an iris adjusts the sensitivity of all of the pixels togetherof a camera. Thus, the active pixel camera automatically adjusts to theincident light on a pixel-by-pixel basis. An active pixel camera differsfrom an active infrared sensor in that an active infrared sensor isgenerally a single pixel sensor that measures the reflection of infraredlight from an object. In some cases, as in the HDRC camera, the outputof each pixel is a logarithm of the incident light thus giving a highdynamic range to the camera. This is similar to the technique used tosuppress the effects of thermal gradient distortion of ultrasonicsignals. Thus, if the incident radiation changes in magnitude by1,000,000, for example, the output of the pixel may change by a factorof only 6.

A dynamic pixel camera is a camera having a plurality of pixels andwhich provides the ability to pick and choose which pixels should beobserved, as long as they are contiguous.

An HDRC camera is a type of active pixel camera where the dynamic rangeof each pixel is considerably broader. An active pixel cameramanufactured by the Photobit Corporation has a dynamic range of 70 dbwhile an IMS Chips camera, an HDRC camera manufactured by anothermanufacturer, has a dynamic range of 120 db. Thus, the HDRC camera has a100,000 times greater range of light sensitivity than the Photobitcamera.

The accuracy of the optical occupant sensor is dependent upon theaccuracy of the camera. The dynamic range of light within a vehicle canexceed 120 decibels. When a car is driving at night, for example, verylittle light is available whereas when driving in a bright sunlight,especially in a convertible, the light intensity can overwhelm manycameras. Additionally, the camera must be able to adjust rapidly tochanges in light caused by, for example, the emergence of the vehiclefrom tunnel, or passing by other obstructions such as trees, buildings,other vehicles, etc. which temporarily block the sun and can cause astrobing effect at frequencies approaching 1 kHz.

As mentioned, the IMS HDRC technology provides a 120 dB dynamicintensity response at each pixel in a monochromatic mode. The technologyhas a 1 million to one dynamic range at each pixel. This preventsblooming, saturation and flaring normally associated with CMOS and CCDcamera technology. This solves a problem that will be encountered in anautomobile when going from a dark tunnel into bright sunlight. Such arange can even exceed the 120 dB intensity.

There is also significant infrared radiation from bright sunlight andfrom incandescent lights within the vehicle. Such situations may evenexceed the dynamic range of the HDRC camera and additional filtering maybe required. Changing the bias on the receiver array, the use of amechanical iris, or of electrochromic glass or liquid crystal, or a Kerror Pockel cell can provide this filtering on a global basis but not at apixel level. Filtering can also be used with CCD arrays, but the amountof filtering required is substantially greater than for the HDRC camera.A notch filter can be used to block significant radiation from the sun,for example. This notch filter can be made as a part of the lens throughthe placement of various coatings onto the lens surface.

Liquid crystals operate rapidly and give as much as a dynamic range of10,000 to 1 but may create a pixel interference affect. Electrochromicglass operates more slowly but more uniformly thereby eliminating thepixel affect. The pixel effect arises whenever there is one pixel devicein front of another. This results in various aliasing, Moiré patternsand other ambiguities. One way of avoiding this is to blur the image.Another solution is to use a large number of pixels and combine groupsof pixels to form one pixel of information and thereby to blur the edgesto eliminate some of the problems with aliasing and Moiré patterns. Analternate to the liquid crystal device is the suspended particle deviceor SPD as discussed herein. Other alternatives include spatial lightmonitors such as Pockel or Kerr cells also discussed herein.

One straightforward approach is the use of a mechanical iris. Standardcameras already have response times of several tens of millisecondsrange. They will switch, for example, in a few frames on a typical videocamera (1 frame=0.033 seconds). This is sufficiently fast forcategorization but much too slow for dynamic out-of-position tracking.

An important feature of the IMS Chips HDRC camera is that the fulldynamic range is available at each pixel. Thus, if there are significantvariations in the intensity of light within the vehicle, and therebyfrom pixel to pixel, such as would happen when sunlight streams andthrough a window, the camera can automatically adjust and provide theoptimum exposure on a pixel by pixel basis. The use of the camera havingthis characteristic is beneficial to the invention described herein andcontributes significantly to system accuracy. CCDs have a rather limiteddynamic range due to their inherent linear response and consequentlycannot come close to matching the performance of human eyes. A keyadvantage of the IMS Chips HDRC camera is its logarithmic response whichcomes closest to matching that of the human eye. The IMS HDRC camera isalso useful in monitoring cargo containers and truck trailers where verylittle light is available when the door is shut. A small IR LED then canprovide the necessary light at a low power consumption which isconsistent with a system that may have to operate for long periods onbattery power.

Another approach, which is applicable in some vehicles at some times, isto record an image without the infrared illumination and then a secondimage with the infrared illumination and to then subtract the firstimage from the second image. In this manner, illumination caused bynatural sources such as sunlight or even from light bulbs within thevehicle can be subtracted out. Using the logarithmic pixel system of theIMS Chips camera, care must be taken to include the logarithmic effectduring the subtraction process. For some cases, natural illuminationsuch as from the sun, light bulbs within the vehicle, or radiationemitted by the object itself can be used alone without the addition of aspecial source of infrared illumination as discussed below.

Other imaging systems such as CCD arrays can also of course be used withat least one of the inventions disclosed herein. However, the techniqueswill be different since the camera is very likely to saturate whenbright light is present and to require the full resolution capability,when the light is dim, of the camera iris and shutter speed settings toprovide some compensation. Generally, when practicing at least one ofthe inventions disclosed herein, the interior of the passengercompartment will be illuminated with infrared radiation.

One novel solution is to form the image in memory by adding up asequence of very short exposures. The number stored in memory would bethe sum of the exposures on a pixel by pixel basis and the problem ofsaturation disappears since the memory location can be made as floatingpoint numbers. This then permits the maximum dynamic range but requiresthat the information from all of the pixels be removed at high speed. Insome cases, each pixel would then be zeroed while in others, the chargecan be left on the pixel since when saturation occurs the relevantinformation will already have been obtained.

There are other bright sources of infrared that must be accounted for.These include the sun and any light bulbs that may be present inside thevehicle. This lack of a high dynamic range inherent with the CCDtechnology requires the use of an iris, fast electronic shutter, liquidcrystal, Kerr or Pockel cell, or electrochromic glass filter to beplaced between the camera and the scene. Even with these filtershowever, some saturation can take place with CCD cameras under brightsun or incandescent lamp exposure. This saturation reduces the accuracyof the image and therefore the accuracy of the system. In particular,the training regimen that must be practiced with CCD cameras is moresevere since all of the saturation cases must be considered since thecamera may be unable to appropriately adjust. Thus, although CCD camerascan be used, HDRC logarithmic cameras such as manufactured by IMS Chipsare preferred. They not only provide a significantly more accurate imagebut also significantly reduce the amount of training effort andassociated data collection that must be undertaken during thedevelopment of the neural network algorithm or other computationalintelligence system. In some applications, it is possible to use othermore deterministic image processing or pattern recognition systems thanneural networks.

Another very important feature of the HDRC camera from IMS Chips is thatthe shutter time is constant at less than 100 ns irrespective ofbrightness of the scene. The pixel data arrives at constant ratesynchronous with the internal imager clock. Random access to each pixelfacilitates high-speed intelligent access to any sub-frame (block) sizeor sub-sampling ratio and a trade-off of frame speed and frame sizetherefore results. For example, a scene with 128 K pixels per frame canbe taken at 120 frames per second, or about 8 milliseconds per frame,whereas a sub-frame can be taken in run at as high as 4000 frames persecond with 4 K pixels per frame. This combination allows the maximumresolution for the identification and classification part of theoccupant sensor problem while permitting a concentration on thoseparticular pixels which track the head or chest for dynamicout-of-position tracking. In fact, the random access features of thesecameras can be used to track multiple parts of the image simultaneouslywhile ignoring the majority of the image, and do so at very high speed.For example, the head can be tracked simultaneously with the chest bydefining two separate sub-frames that need not be connected. This randomaccess pixel capability, therefore, is optimally suited for recognizingand tracking vehicle occupants. It is also suited for monitoring theenvironment outside of the vehicle for the purposes of blind spotdetection, collision avoidance and anticipatory sensing. PhotobitCorporation of 135 North Los Robles Ave., Suite 700, Pasadena, Calif.91101 manufactures a camera with some characteristics similar to the IMSChips camera. Other competitive cameras can be expected to appear on themarket.

Photobit refers to their Active Pixel Technology as APS. According toPhotobit, in the APS, both the photo detector and readout amplifier arepart of each pixel. This allows the integrated charge to be convertedinto a voltage in the pixel that can then be read out over X-Y wiresinstead of using a charge domain shift register as in CCDs. This columnand row addressability (similar to common DRAM) allows for window ofinterest readout (windowing) which can be utilized for on chipelectronic pan/tilt and zoom. Windowing provides added flexibility inapplications, such as disclosed herein, needing image compression,motion detection or target tracking. The APS utilizes intra-pixelamplification in conjunction with both temporal and fixed pattern noisesuppression circuitry (i.e., correlated double sampling), which producesexceptional imagery in terms of wide dynamic range (˜75 dB) and lownoise (˜15 e-rms noise floor) with low fixed pattern noise (<0.15% sat).Unlike CCDs, the APS is not prone to column streaking due to bloomingpixels. This is because CCDs rely on charge domain shift registers thatcan leak charge to adjacent pixels when the CCD registers overflows.Thus, bright lights “bloom” and cause unwanted streaks in the image. Theactive pixel can drive column busses at much greater rates than passivepixel sensors and CCDs. On-chip analog-to-digital conversion (ADC)facilitates driving high speed signals off chip. In addition, digitaloutput is less sensitive to pickup and crosstalk, facilitating computerand digital controller interfacing while increasing system robustness. Ahigh speed APS recently developed for a custom binary output applicationproduced over 8,000 frames per second, at a resolution of 128×128pixels. It is possible to extend this design to a 1024×1024 array sizeand achieve greater than 1000 frames per second for machine vision. Allof these features can be important to many applications of at least oneof the inventions disclosed herein.

These advanced cameras, as represented by the HDRC and the APS cameras,now make it possible to more accurately monitor the environment in thevicinity of the vehicle. Previously, the large dynamic range ofenvironmental light has either blinded the cameras when exposed tobright light or else made them unable to record images when the lightlevel was low. Even the HDRC camera with its 120 dB dynamic range may bemarginally sufficient to handle the fluctuations in environmental lightthat occur. Thus, the addition of a electrochromic, liquid crystal, SPD,spatial light monitors or other similar filter may be necessary. This isparticularly true for cameras such as the Photobit APS camera with its75 dB dynamic range.

At about 120 frames per second, these cameras are adequate for caseswhere the relative velocity between vehicles is low. There are manycases, however, where this is not the case and a much higher monitoringrate is required. This occurs for example, in collision avoidance andanticipatory sensor applications. The HDRC camera is optimally suitedfor handling these cases since the number of pixels that are beingmonitored can be controlled resulting in a frame rate as high as about4000 frames per second with a smaller number of pixels.

Another key advantage of the HDRC camera is that it is quite sensitiveto infrared radiation in the 0.8 to 1 micron wavelength range. Thisrange is generally beyond visual range for humans permitting this camerato be used with illumination sources that are not visible to the humaneye. A notch filter is frequently used with the camera to eliminateunwanted wavelengths. These cameras are available from the Institute forMicroelectronics (IMS Chips), Allamndring 30a, D-70569 Stuttgart,Germany with a variety of resolutions ranging from 512 by 256 to 720 by576 pixels and can be custom fabricated for the resolution and responsetime required.

One problem with high dynamic range cameras, particularly those makinguse of a logarithmic compression is that the edges of objects in thefield of view tend to wash out and the picture loses a lot of contrast.This causes problems for edge detecting algorithms and thus reduces theaccuracy of the system. There are a number of other different methods ofachieving a high dynamic range without sacrificing contrast. One systemby Nayar, as discussed herein, takes a picture using adjacent pixelswith different radiation blocking filers. Four such pixel types are usedallowing Nayar to essentially obtain 4 separate pictures with one snapof the shutter. Software then selects which of the four pixels to usefor each part of the image so that the dark areas receive one exposureand somewhat brighter areas another exposure and so on. The brightestpixel receives all of the incident light, the next brightest filtershalf of the light, the next brightest half again and the dullest pixelhalf again. Other ratios could be used as could more levels of pixels,e.g., eight instead of four. Experiments have shown that this issufficient to permit a good picture to be taken when bright sunlight isstreaming into a dark room. A key advantage of this system is that thefull frame rate is available and the disadvantage is that only 25% ofthe pixels are in fact used to form the image.

Another system drains the charge off of the pixels as the picture isbeing taken and stored the integrated results in memory. TFA technologylends itself to this implementation. As long as the memory capacity issufficient, the pixel never saturates. An additional approach is to takemultiple images at different iris or shutter settings and combine themin much the same way as with the Nayar method. A still differentapproach is to take several pictures at a short shutter time or a smalliris setting and combine the pictures in a processor or otherappropriate device. In this manner, the effective dynamic range of thecamera can be extended. This method may be too slow for some dynamicapplications.

3.5 Fisheye Lens, Pan and Zoom

Infrared waves are shown coming from the front and back transducerassemblies 54 and 55 in FIG. 8C. FIG. 8D illustrates two optical systemseach having a source of infrared radiation and a CCD, CMOS, FPR, TFA orQWIP array receiver. The price of such arrays has dropped dramaticallyrecently making most of them practical for interior and exterior vehiclemonitoring. In this embodiment, transducers 54 and 55 are CMOS arrayshaving 160 pixels by 160 pixels covered by a lens. In some applications,this can create a “fisheye” effect whereby light from a wide variety ofdirections can be captured. One such transducer placed by the dome lightor other central position in the vehicle headliner, such as thetransducer designated 54, can monitor the entire vehicle interior withsufficient resolution to determine the occupancy of the vehicle, forexample. Imagers such as those used herein are available from MarshallElectronics Inc. of Culver City, Calif. and others. A fisheye lens is “. . . a wide-angle photographic lens that covers an angle of about 180°,producing a circular image with exaggerated foreshortening in the centerand increasing distortion toward the periphery”. (The American HeritageDictionary of the English Language, Third Edition, 1992 by HoughtonMifflin Company). This distortion of a fisheye lens can be substantiallychanged by modifying the shape of the lens to permit particular portionsof the interior passenger compartment to be observed. Also, in manycases the full 180° is not desirable and a lens which captures a smallerangle may be used. Although primarily spherical lenses are illustratedherein, it is understood that the particular lens design will depend onthe location in the vehicle and the purpose of the particular receiver.A fisheye lens can be particularly useful for some truck trailer, cargocontainer, railroad car and automobile trunk monitoring cases.

A camera that provides for pan and zoom using a fisheye lens isdescribed in U.S. Pat. No. 5,185,667 and is applicable to at least oneof the inventions disclosed herein. Here, however, it is usually notnecessary to remove the distortion since the image will in general notbe viewed by a human but will be analyzed by software. One exception iswhen the image is sent to emergency services via telematics. In thatcase, the distortion removal is probably best done at the EMS site.

Although a fisheye camera has been discussed above, other types ofdistorting lenses or mirrors can be used to accomplished particularobjectives. A distorting lens or mirror, for example, can have theeffect of dividing the image into several sub-pictures so that theavailable pixels can cover more than one area of a vehicle interior orexterior. Alternately, the volume in close proximity to an airbag, forexample, can be allocated a more dense array of pixels so thatmeasurements of the location of an occupant relative to the airbag canbe more accurately achieved. Numerous other objectives can now beenvisioned which can now be accomplished with a reduction in the numberof cameras or imagers through either distortion or segmenting of theoptical field.

Another problem associated with lens is cleanliness. In general, theoptical systems of these inventions comprise methods to test for thevisibility through the lens and issue a warning when that visibilitybegins to deteriorate. Many methods exist for accomplishing this featincluding the taking of an image when the vehicle is empty and notmoving and at night. Using neural networks, for example, or some othercomparison technique, a comparison of the illumination reaching theimager can be compared with what is normal. A network can be trained onempty seats, for example, in all possible positions and compared withthe new image. Or, those pixels that correspond to any movable surfacein the vehicle can be removed from the image and a brightness test onthe remaining pixels used to determine lens cleanliness.

Once a lens has been determined to be dirty, then either a warning lightcan be set telling the operator to visit the dealer or a method ofcleaning the lens automatically invoked. One such method for nightvision systems is disclosed in WO0234572. Another, which is one on theinventions disclosed herein, is to cover the lens with a thin film. Thisfilm may be ultrasonically excited thereby greatly minimizing thetendency for it to get dirty and/or the film can be part of a roll offilm that is advanced when the diagnostic system detects a dirty lensthereby placing a new clean surface in front of the imager. The filmroll can be sized such that under normal operation, the roll would lastsome period such as 20 years. A simple, powerless mechanism can bedesigned that will gradually advance the film across the lens over aperiod of 10 to 20 years using the normal daily thermal cycling to causerelative expansion and contraction of materials with differing thermalexpansion coefficients.

4. 3D Cameras

Optical sensors can be used to obtain a three-dimensional measurement ofthe object through a variety of methods that use time of flight,modulated light and phase measurement, quantity of light received withina gated window, structured light and triangulation etc. Some of thesetechniques are discussed in U.S. Pat. No. 6,393,133 and below.

4.1 Stereo

One method of obtaining a three-dimensional image is illustrated in FIG.8D wherein transducer 24 is an infrared source having a widetransmission angle such that the entire contents of the front driver'sseat is illuminated. Receiving imager transducers 23 and 25 are shownspaced apart so that a stereographic analysis can be made by the controlcircuitry 20. This circuitry 20 contains a microprocessor withappropriate pattern recognition algorithms along with other circuitry asdescribed above. In this case, the desired feature to be located isfirst selected from one of the two returned images from either imagingtransducer 23 or 25. The software then determines the location of thesame feature, through correlation analysis or other methods, on theother image and thereby, through analysis familiar to those skilled inthe art, determines the distance of the feature from the transducers bytriangulation.

As the distance between the two or more imagers used in the stereoconstruction increases, a better and better model of the object beingimaged can be obtained since more of the object is observable. On theother hand, it becomes increasingly difficult to pair up points thatoccur in both images. Given sufficient computational resources, this nota difficult problem but with limited resources and the requirement totrack a moving occupant during a crash, for example, the problem becomesmore difficult. One method to ease the problem is to project onto theoccupant, a structured light that permits a recognizable pattern to beobserved and matched up in both images. The source of this projectionshould lie midway between the two imagers. By this method, a rapidcorrespondence between the images can be obtained.

On the other hand, if a source of structured light is available at adifferent location than the imager, then a simpler three-dimensionalimage can be obtained using a single imager. Furthermore, the model ofthe occupant really only needs to be made once during the classificationphase of the process and there is usually sufficient time to accomplishthat model with ordinary computational power. Once the model has beenobtained, then only a few points need be tracked by either one or bothof the cameras.

Another method exists whereby the displacement between two images fromtwo cameras is estimated using a correlator. Such a fast correlator hasbeen developed by Professor Lukin of Kyiv, Ukraine in conjunction withhis work on noise radar. This correlator is very fast and can probablydetermine the distance to an occupant at a rate sufficient for trackingpurposes.

4.2 Distance by Focusing

In the above-described imaging systems, a lens within a receptorcaptures the reflected infrared light from the head or chest of thedriver, or other object to be monitored, and displays it onto an imagingdevice (CCD, CMOS, FPA, TFA, QWIP or equivalent) array. For thediscussion of FIGS. 5, 12 and 13 at least, either CCD or the word“imager” will be used to include all devices which are capable ofconverting light frequencies, including infrared, into electricalsignals. In one method of obtaining depth from focus, the CCD is scannedand the focal point of the lens is altered, under control of anappropriate circuit, until the sharpest image of the driver's head orchest, or other object, results and the distance is then known from thefocusing circuitry. This trial and error approach may require the takingof several images and thus may be time consuming and perhaps too slowfor occupant tracking during pre-crash braking.

The time and precision of this measurement is enhanced if two receptors(e.g., lenses) are used which can either project images onto a singleCCD or onto separate CCDs. In the first case, one of the lenses could bemoved to bring the two images into coincidence while in the other case,the displacement of the images needed for coincidence would bedetermined mathematically. Other systems could be used to keep track ofthe different images such as the use of filters creating differentinfrared frequencies for the different receptors and again using thesame CCD array. In addition to greater precision in determining thelocation of the occupant, the separation of the two receptors can alsobe used to minimize the effects of hands, arms or other extremitieswhich might be very close to the airbag. In this case, where thereceptors are mounted high on the dashboard on either side of thesteering wheel, an arm, for example, would show up as a thin object butmuch closer to the airbag than the larger body parts and, therefore,easily distinguished and eliminated, permitting the sensors to determinethe distance to the occupant's chest. This is one example of the use ofpattern recognition.

An alternate method is to use a lens with a short focal length. In thiscase, the lens is mechanically focused, e.g., automatically, directly orindirectly, by the control circuitry 20, to determine the clearest imageand thereby obtain the distance to the object. This is similar tocertain camera auto-focusing systems such as one manufactured by Fuji ofJapan. Again this is a time consuming method. Other methods can be usedas described in patents and patent applications referenced above.

Instead of focusing the lens, the lens could be moved relative to thearray to thereby adjust the image on the array. Instead of moving thelens, the array could be moved to achieve the proper focus. In addition,it is also conceivable that software could be used to focus the imagewithout moving the lens or the array especially if at least two imagesare available.

An alternative is to use the focusing systems described in U.S. Pat.Nos. 5,193,124 and 5,003,166. These systems are quite efficientrequiring only two images with different camera settings. Thus, if thereis sufficient time to acquire an image, change the camera settings andacquire a second image, this system is fine and can be used with theinventions disclosed herein. Once the position of the occupant has beendetermined for one point in time, then the process may not have to berepeated as a measurement of the size of a part of an occupant can serveas a measure of its relative location compared to the previous imagefrom which the range was obtained. Thus, other than the requirement of asomewhat more expensive imager, the system of the '124 and '166 patentsis fine. The accuracy of the range is perhaps limited to a fewcentimeters depending on the quality of the imager used. Also, ifmultiple ranges to multiple objects are required, then the processbecomes a bit more complicated.

4.3 Ranging

The scanning portion of a pulse laser radar device can be accomplishedusing rotating mirrors, vibrating mirrors, or preferably, a solid statesystem, for example one utilizing TeO₂ as an optical diffraction crystalwith lithium niobate crystals driven by ultrasound (although other solidstate systems not necessarily using TeO₂ and lithium niobate crystalscould also be used) which is an example of an acoustic optical scanner.An alternate method is to use a micromachined mirror, which is supportedat its center and caused to deflect by miniature coils or equivalentMEMS device. Such a device has been used to provide two-dimensionalscanning to a laser. This has the advantage over the TeO₂—lithiumniobate technology in that it is inherently smaller and lower cost andprovides two-dimensional scanning capability in one small device. Themaximum angular deflection that can be achieved with this process is onthe order of about 10 degrees. Thus, a diverging lens or equivalent willbe needed for the scanning system.

Another technique to multiply the scanning angle is to use multiplereflections off of angled mirror surfaces. A tubular structure can beconstructed to permit multiple interior reflections and thus amultiplying effect on the scan angle.

An alternate method of obtaining three-dimensional information from ascanning laser system is to use multiple arrays to replace the singlearrays used in FIG. 8A. In the case, the arrays are displaced from eachother and, through triangulation, the location of the reflection fromthe illumination by a laser beam of a point on the object can bedetermined in a manner that is understood by those skilled in the art.Alternately, a single array can be used with the scanner displaced fromthe array.

A new class of laser range finders has particular application here. Thisproduct, as manufactured by Power Spectra, Inc. of Sunnyvale, Calif., isa GaAs pulsed laser device which can measure up to 30 meters with anaccuracy of <2 cm and a resolution of <1 cm. This system can beimplemented in combination with transducer 24 and one of the receivingtransducers 23 or 25 may thereby be eliminated. Once a particularfeature of an occupying item of the passenger compartment has beenlocated, this device is used in conjunction with an appropriate aimingmechanism to direct the laser beam to that particular feature. Thedistance to that feature can then be known to within 2 cm and withcalibration even more accurately. In addition to measurements within thepassenger compartment, this device has particular applicability inanticipatory sensing and blind spot monitoring applications exterior tothe vehicle. An alternate technology using range gating to measure thetime of flight of electromagnetic pulses with even better resolution canbe developed based on the teaching of the McEwan patents listed above.

A particular implementation of an occupant position sensor having arange of from 0 to 2 meters (corresponding to an occupant position offrom 0 to 1 meter since the signal must travel both to and from theoccupant) using infrared is illustrated in the block diagram schematicof FIG. 13. This system was designed for automobile occupant sensing anda similar system having any reasonable range up to and exceeding 100meters can be designed on the same principles for other monitoringapplications. The operation is as follows. A 48 MHz signal, f1, isgenerated by a crystal oscillator 81 and fed into a frequency tripler 82which produces an output signal at 144 MHz. The 144 MHz signal is thenfed into an infrared diode driver 83 which drives the infrared diode 84causing it to emit infrared light modulated at 144 MHz and a referencephase angle of zero degrees. The infrared diode 84 is directed at thevehicle occupant. A second signal f2 having a frequency of 48.05 MHz,which is slightly greater than f1, is similarly fed from a crystaloscillator 85 into a frequency tripler 86 to create a frequency of144.15 MHz. This signal is then fed into a mixer 87 which combines itwith the 144 MHz signal from frequency tripler 82. The combined signalfrom the mixer 87 is then fed to filter 88 which removes all signalsexcept for the difference, or beat frequency, between 3 times f1 and 3times f2, of 150 kHz. The infrared signal which is reflected from theoccupant is received by receiver 89 and fed into pre-amplifier 91, aresistor 90 to bias being coupled to the connection between the receiver89 and the pre-amplifier 91. This signal has the same modulationfrequency, 144 MHz, as the transmitted signal but now is out of phasewith the transmitted signal by an angle x due to the path that thesignal took from the transmitter to the occupant and back to thereceiver.

The output from pre-amplifier 91 is fed to a second mixer 92 along withthe 144.15 MHz signal from the frequency tripler 86. The output frommixer 92 is then amplified by an automatic gain amplifier 93 and fedinto filter 94. The filter 94 eliminates all frequencies except for the150 kHz difference, or beat, frequency, in a similar manner as was doneby filter 88. The resulting 150 kHz frequency, however, now has a phaseangle x relative to the signal from filter 88. Both 150 kHz signals arenow fed into a phase detector 95 which determines the magnitude of thephase angle x. It can be shown mathematically that, with the abovevalues, the distance from the transmitting diode to the occupant isx/345.6 where x is measured in degrees and the distance in meters. Thevelocity can also be obtained using the distance measurement asrepresented by 96. An alternate method of obtaining distance informationis to use the teachings of the McEwan patents discussed herein.

As reported above, cameras can be used for obtaining three-dimensionalimages by modulation of the illumination as taught in U.S. Pat. No.5,162,861. Use of a ranging device for occupant sensing is believed tohave been first disclosed by the current assignee. More recent attemptsinclude the PMD camera as disclosed in PCT application WO09810255 andsimilar concepts disclosed in U.S. Pat. Nos. 6,057,909 and 6,100,517.

Note that although the embodiment in FIG. 13 uses near infrared, it ispossible to use other frequencies of energy without deviating from thescope of the invention. In particular, there are advantages in using theshort wave (SWIR), medium wave (MWIR) and long wave (LWIR) portions ofthe infrared spectrum as the interact in different and interesting wayswith living occupants as described herein and in the book Alien Visionreferenced above.

4.4 Pockel or Kerr Cell for Determining Range

Pockel and Kerr cells are well known in optical laboratories. They actas very fast shutters (up to 10 billion cycles per second) and as suchcan be used to range-gate the reflections based on distance giving arange resolution of up to 3 cm without the use of phase techniques todivide the interval into parts or sub millimeter resolution usingphasing techniques. Thus, through multiple exposures the range to allreflecting surfaces inside and outside of the vehicle can be determinedto any appropriate degree of accuracy. The illumination is transmitted,the camera shutter opened and the cell allows only that reflected lightto enter the camera that arrived at the cell a precise time range afterthe illumination was initiated.

These cells are part of a class of devices called spatial lightmodulators (SLM). One novel application of an SLM is reported in U.S.Pat. No. 5,162,861. In this case, an SLM is used to modulate the lightreturning from a transmitted laser pulse that is scattered from atarget. By comparing the intensities of the modulated and unmodulatedimages, the distance to the target can be ascertained. Using a SLM inanother manner, the light valve can be kept closed for all ranges exceptthe ones of interest. By changing the open time of the SLM, only returnsfrom certain distances are permitted to pass through to the imager. Byselective changing the opened time, the range to the target can be“range-gated” and thereby accurately determined. Thus, the outgoinglight need not be modulated and a scanner is not necessary unless thereis a need to overcome the power of the sun reflecting off of the objectof interest. This form of range-gating can of course be used for eitherexternal or internal applications.

4.5 Thin Film on ASIC (TFA)

Since the concepts of using cameras for monitoring the passengercompartment of a vehicle and measuring distance to a vehicle occupantbased on the time of flight were first disclosed in commonly assignedabove-referenced patents, several improvements have been reported in theliterature including the thin film on ASIC (TFA) (references 6-11 of the'957 application) and photonic mixing device (PMD) (reference 12 of the'957 application) camera technologies. Both of these technologies andcombinations thereof are good examples of devices that can be used inpracticing the inventions herein and those in above-referenced patentsand applications for monitoring both inside and exterior to a vehicle.

An improvement to these technologies is to use noise or pseudo noisemodulation for a PMD-like device to permit more accurate distance toobject determination especially for exterior to the vehicle monitoringthrough correlation of the generated and reflected modulation sequences.This has the further advantage that systems from different vehicles willnot interfere with each other.

The TFA is an example of a high dynamic range camera (HDRC) the use ofwhich for interior monitoring was disclosed in U.S. Pat. No. 6,393,133.Since there is direct connection between each pixel and an associatedelectronic circuit, the potential exists for range gating the sensor toisolate objects between certain limits thus simplifying theidentification process by eliminating reflections from objects that arecloser or further away than the object of interest. A further advantageof the TFA is that it can be doped to improve its sensitivity toinfrared and it also can be fabricated as a three-color camera system.

Another novel HDRC camera is disclosed by Nayar (reference 13 in the'957 application) and involves varying the sensitivity of pixels in theimager. Each of four adjacent pixels has a different exposuresensitivity and an algorithm is presented that combines the fourexposures in a manner that loses little resolution but provides a highdynamic range picture. This particularly simple system is a preferredapproach to handling the dynamic range problem in several monitoringapplications of at least one of the inventions disclosed herein.

A great deal of development effort has gone into automatic camerafocusing systems such as described in the Scientific American Article“Working Knowledge: Focusing in a Flash” (reference 14). The technologyis now to the point that it can be taught to focus on a particularobject, such as the head or chest of an occupant, or other object, andmeasure the distance to the object to within approximately 1 inch. Ifthis technology is coupled with the Nayar camera, a very low cost semi3D high dynamic range camera or imager results that is sufficientlyaccurate for locating an occupant in the passenger compartment or anobject in another container. If this technology is coupled with an eyelocator and the distance to the eyes of the occupant are determined,then a single camera is all that is required for either the driver orpassenger. Such a system would display a fault warning when it is unableto find the occupant's eyes. Such a system is illustrated in FIGS. 35and 36.

Thin film on ASIC technology, as described in Lake, D. W. “TFATechnology: The Coming Revolution in Photography”, Advanced ImagingMagazine, April, 2002 shows promise of being the next generation ofimager for automotive and other vehicle monitoring applications. Theanticipated specifications for this technology, as reported in the Lakearticle, are:

Dynamic Range 120 db Sensitivity 0.01 lux Anti-blooming 1,000,000:1Pixel Density 3,200,000 Pixel Size 3.5 um Frame Rate 30 fps DC Voltage1.8 v Compression 500 to 1

All of these specifications, except for the frame rate, are attractivefor occupant sensing. It is believed that the frame rate can be improvedwith subsequent generations of the technology. Some advantages of thistechnology for occupant sensing include the possibility of obtaining athree-dimensional image by varying the pixel on time in relation to amodulated illumination in a simpler manner than that proposed with thePMD imager or with a Pockel or Kerr cell. The ability to build theentire package on one chip will reduce the cost of this imager comparedwith two or more chips required by current technology.

TFA thus appears to be a major breakthrough when used in the interiorand exterior imaging systems. Its use in these applications falls withinthe teachings of the inventions disclosed herein.

5. Glare Control

The headlights of oncoming vehicles frequently make it difficult for thedriver of a vehicle to see the road and safely operate the vehicle. Thisis a significant cause of accidents and much discomfort. The problem isespecially severe during bad weather where rain can cause multiplereflections. Opaque visors are now used to partially solve this problembut they do so by completely blocking the view through a large portionof the window and therefore cannot be used to cover the entirewindshield. Similar problems happen when the sun is setting or risingand the driver is operating the vehicle in the direction of the sun.U.S. Pat. No. 4,874,938 attempts to solve this problem through the useof a motorized visor but although it can block some glare sources, italso blocks a substantial portion of the field of view.

The vehicle interior monitoring system disclosed herein can contributeto the solution of this problem by determining the position of thedriver's eyes relative to the parts of the vehicles which may be a framedefining the passenger compartment, a mirror or another vehicularcomponent whose use is variable depending on the location of the eyes ofan occupant. If separate sensors are used to sense the direction of thelight from the on-coming vehicle or the sun, and through the use ofelectrochromic glass, a liquid crystal device, suspended particle deviceglass (SPD) or other appropriate technology, a portion of thewindshield, or special visor, can be darkened to impose a filter betweenthe eyes of the driver and the light source. Electrochromic glass is amaterial where the transparency of the glass can be changed through theapplication of an electric current. The term “liquid crystal” as usedherein will be used to represent the class of all such materials wherethe optical transmissibility can be varied electrically orelectronically. Electrochromic products are available from Gentex ofZeeland, Mich., and Donnelly of Holland, Mich. Other systems forselectively imposing a filter between the eyes of an occupant and thelight source are currently under development.

By dividing the windshield into a controlled grid or matrix ofcontiguous areas and through feeding the current into the windshieldfrom orthogonal directions, selective portions of the windshield can bedarkened as desired. Other systems for selectively imposing a filterbetween the eyes of an occupant and the light source are currently underdevelopment. One example is to place a transparent sun visor type devicebetween the windshield and the driver to selectively darken portions ofthe visor as described above for the windshield.

5.1 Windshield

FIG. 25 illustrates how such a system operates for the windshield. Asensor 135 located on vehicle 136 determines the direction of the light138 from the headlights of oncoming vehicle 137. Sensor 135 is comprisedof a lens and a charge-coupled device (CCD), CMOS or similar device,with appropriate software or electronic circuitry that determines whichelements of the CCD are being most brightly illuminated. An algorithmstored in processor 20 then calculates the direction of the light fromthe oncoming headlights based on the information from the CCD, or CMOSdevice. Usually two systems 135 are required to fix the location of theoffending light. Transducers 6, 8 and 10 determine the probable locationof the eyes of the operator 30 of vehicle 136 in a manner such asdescribed herein. In this case, however, the determination of theprobable locus of the driver's eyes is made with an accuracy of adiameter for each eye of about 3 inches (7.5 cm). This calculationsometimes will be in error especially for ultrasonic occupant sensingsystems and provision is made for the driver to make an adjustment tocorrect for this error as described below.

The windshield 139 of vehicle 136 comprises electrochromic glass, aliquid crystal, SPD device or similar system, and is selectivelydarkened at area 140, FIG. 25A, due to the application of a currentalong perpendicular directions 141 and 142 of windshield 139. Theparticular portion of the windshield to be darkened is determined byprocessor 20. Once the direction of the light from the oncoming vehicleis known and the locations of the driver's eyes are known, it is amatter of simple trigonometry to determine which areas of the windshieldmatrix should be darkened to impose a light filter between theheadlights and the driver's eyes. This is accomplished by the processor20. A separate control system, not shown, located on the instrumentpanel, steering wheel or at some other convenient location, allows thedriver to select the amount of darkening accomplished by the system fromno darkening to maximum darkening. In this manner, the driver can selectthe amount of light that is filtered to suit his particular physiology.Alternately, this process can take place automatically. The sensor 135can either be designed to respond to a single light source or tomultiple light sources to be sensed and thus multiple portions of thevehicle windshield 139 to be darkened. Unless the camera is located onthe same axis at the eyes of the driver, two cameras would in general berequired to determine the distance of the glare causing object from theeyes of the driver. Without this third dimension, two glare sources thatare on the same axis to the camera could be on different axes to thedriver, for example.

As an alternative to locating the direction of the offending lightsource, a camera looking at the eyes of the driver can determine whenthey are being subjected to glare and then impose a filter. A trial anderror process or through the use of structured light created by apattern on the windshield, determines where to create the filter toblock the glare.

More efficient systems are now becoming available to permit asubstantial cost reduction as well as higher speed selective darkeningof the windshield for glare control. These systems permit covering theentire windshield which is difficult to achieve with LCDs. For example,such systems are made from thin sheets of plastic film, sometimes withan entrapped liquid, and can usually be sandwiched between the twopieces of glass that make up a typical windshield. The development ofconductive plastics permits the addressing and thus the manipulation ofpixels of a transparent film that previously was not possible. These newtechnologies will now be discussed.

If the objective is for glare control, then the Xerox Gyricon technologyapplied to windows can be appropriate. Previously, this technology hasonly been used to make e-paper and a modification to the technology isnecessary for it to work for glare control. Gyricon is a thin layer oftransparent plastic full of millions of small black and white or red andwhite beads, like toner particles. The beads are contained in anoil-filled cavity. When voltage is applied, the beads rotate to presenta colored side to the viewer. The advantages of Gyricon are: (1) it iselectrically writeable and erasable; (2) it can be re-used thousands oftimes; (3) it does not require backlighting or refreshing; (4) it isbrighter than today's reflective displays; and, (5) it operates on lowpower. The changes required are to cause the colored spheres to rotate90 degrees rather than 180 degrees and to make half of each spheretransparent so that the display switches from opaque to 50% transparent.

Another technology, SPD light control technology from Research FrontiersInc., has been used to darken entire windows but not as a system fordarkening only a portion of the glass or sun visor to impose a selectivefilter to block the sun or headlights of an oncoming vehicle. Althoughit has been used as a display for laptop computers, it has not been usedas a heads-up display (HUD) replacement technology for automobile ortruck windshields.

Both SPD and Gyricon technologies require that the particles be immersedin a fluid so that the particles can move. Since the properties of thefluid will be temperature sensitive, these technologies will varysomewhat in performance over the automotive temperature range. Thepreferred technology, therefore, is plastic electronics although in manyapplications either Gyricon or SPD will also be used in combination withplastic electronics, at least until the technology matures. Currentlyplastic electronics can only emit light and not block it. However,research is ongoing to permit it to also control the transmission oflight.

The calculations of the location of the driver's eyes using acousticsystems may be in error and therefore provision must be made to correctfor this error. One such system permits the driver to adjust the centerof the darkened portion of the windshield to correct for such errorsthrough a knob, mouse pad, joy stick or other input device, on theinstrument panel, steering wheel, door, armrest or other convenientlocation. Another solution permits the driver to make the adjustment byslightly moving his head. Once a calculation as to the location of thedriver's eyes has been made, that calculation is not changed even thoughthe driver moves his head slightly. It is assumed that the driver willonly move his head in a very short time period to center the darkenedportion of the windshield to optimally filter the light from theoncoming vehicle. The monitoring system will detect this initial headmotion and make the correction automatically for future calculations.Additionally, a camera observing the driver or other occupant canmonitor the reflections of the sun or the headlights of oncomingvehicles off of the occupant's head or eyes and automatically adjust thefilter in the windshield or sun visor.

5.2 Glare in Rear View Mirrors

Electrochromic glass is currently used in rear view mirrors to darkenthe entire mirror in response to the amount of light striking anassociated sensor. This substantially reduces the ability of the driverto see objects coming from behind his vehicle. If one rear-approachingvehicle, for example, has failed to dim his lights, the mirror will bedarkened to respond to the light from that vehicle making it difficultfor the driver to see other vehicles that are also approaching from therear. If the rear view mirror is selectively darkened on only thoseportions that cover the lights from the offending vehicle, the driver isable to see all of the light coming from the rear whether the source isbright or dim. This permits the driver to see all of the approachingvehicles not just the one with bright lights.

Such a system is illustrated in FIGS. 26, 26A and 26B wherein rear viewmirror 55 is equipped with electrochromic glass, or comprises a liquidcrystal or similar device, having the capability of being selectivelydarkened, e.g., at area 143. Associated with mirror 55 is a light sensor144 that determines the direction of light 138 from the headlights ofrear approaching vehicle 137. Again, as with the windshield, a stereocamera is used if the camera is not aligned with the eye view path. Thisis easier to accomplish with a mirror due to its much smaller size. Insuch a case, the imager could be mounted on the movable part of themirror and could even look through the mirror from behind. In the samemanner as above, transducers 6, 8 and 10 determine the location of theeyes of the driver 30. The signals from both sensor systems, 6, 8, 10and 144, are combined in the processor 20, where a determination is madeas to what portions of the mirror should be darkened, e.g., area 143.Appropriate currents are then sent to the mirror 55 in a manner similarto the windshield system described above. Again, an alternative solutionis to observe a glare reflection on the face of the driver and removethe glare with a filter.

Note, the rearview mirror is also an appropriate place to display iconsof the contents of the blind spot or other areas surrounding the vehicleas disclosed in U.S. Pat. No. 7,049,945.

5.3 Visor for Glare Control and HUD

FIG. 27 illustrates the interior of a passenger compartment with a rearview mirror assembly 55, a camera for viewing the eyes of the driver 56and a large generally transparent sun visor 145. The sun visor 145 isnormally largely transparent and is made from electrochromic glass,suspended particle glass, a liquid crystal device or equivalent. Thecamera 56 images the eyes of the driver and looks for a reflectionindicating that glare is impinging on the driver's eyes. The camerasystem may have a source of infrared or other frequency illuminationthat would be momentarily activated to aid in locating the driver'seyes. Once the eyes have been located, the camera monitors the areaaround the eyes, or direct reflections from the eyes themselves, for anindication of glare. The camera system in this case would not know thedirection from which the glare is originating; it would only know thatthe glare was present. The glare blocker system then can darken selectedportions of the visor to attempt to block the source of glare and woulduse the observation of the glare from or around the eyes of the driveras feedback information. When the glare has been eliminated, the systemmaintains the filter, perhaps momentarily reducing it from time to timeto see that the source of glare has not stopped.

If the filter is electrochromic glass, a significant time period isrequired to activate the glare filter and therefore a trial and errorsearch for the ideal filter location could be too slow. In this case, anon-recurring spatial pattern can be placed in the visor such that whenlight passes through the visor and illuminates the face of the driver,the location where the filter should be placed can be easily determined.That is, the pattern reflection off of the face of the driver wouldindicate the location of the visor through which the light causing theglare was passing. Such a structured light system can also be used forthe SPD and LCD filters but since they act significantly more rapidly,it would serve only to simplify the search algorithm for filterplacement.

A second photo sensor 135 can also be used pointing through thewindshield to determine only that glare was present. In this manner,when the source of the glare disappears, the filter can be turned off. Amore sophisticated system as described above for the windshield systemwhereby the direction of the light is determined using a camera-typedevice can also be implemented.

The visor 145 is illustrated as substantially covering the frontwindshield in front of the driver. This is possible since it istransparent except where the filter is applied, which would in generalbe a small area. A second visor, not shown, can also be used to coverthe windshield for the passenger side that would also be useful when thelight-causing glare on the driver's eyes enters thought the windshieldin front of the passenger or if a passenger system is also desired. Insome cases, it might even be advantageous to supply a similar visor tocover the side windows but in general, standard opaque visors wouldserve for both the passenger side windshield area and the side windowssince the driver in general only needs to look through the windshield infront of him or her.

A smaller visor can also be used as long as it is provided with apositioning system or method. The visor only needs to cover the eyes ofthe driver. This could either be done manually or by electric motorssimilar to the system disclosed in U.S. Pat. No. 4,874,938. If electricmotors are used, then the adjustment system would first have to move thevisor so that it covered the driver's eyes and then provide the filter.This could be annoying if the vehicle is heading into the sun andturning and/or going up and down hills. In any case, the visor should bemovable to cover any portion of the windshield where glare can getthrough, unlike conventional visors that only cover the top half of thewindshield. The visor also does not need to be close to the windshieldand the closer that it is to the driver, the smaller and thus the lessexpensive it can be.

As with the windshield, the visor of at least one of the inventionsdisclosed herein can also serve as a display using plastic electronicsas described above either with or without the SPD or other filtermaterial. Additionally, visor-like displays can now be placed at manylocations in the vehicle for the display of Internet web pages, movies,games etc. Occupants of the rear seat, for example, can pull down suchdisplays from the ceiling, up from the front seatbacks or out from theB-pillars or other convenient locations.

A key advantage of the systems disclosed herein is the ability to handlemultiple sources of glare in contrast to the system of U.S. Pat. No.4,874,938, which requires that the multiple sources must be closetogether.

5.4 Headlamp Control

In a similar manner, the forward looking camera(s) can also be used tocontrol the lights of vehicle 136 when either the headlights ortaillights of another vehicle are sensed. In this embodiment, the CCDarray is designed to be sensitive to visible light and a separate sourceof illumination is not used. The key to this technology can be the useof trained pattern recognition algorithms and particularly theartificial neural network. Here, as in the other cases above and inpatents and patent applications referenced above, the patternrecognition system is trained to recognize the pattern of the headlightsof an oncoming vehicle or the tail lights of a vehicle in front ofvehicle 136 and to then dim the headlights when either of theseconditions is sensed. It is also trained to not dim the lights for otherreflections such as reflections off of a sign post or the roadway. Oneproblem is to differentiate taillights where dimming is desired fromdistant headlights where dimming is not desired. At least threetechniques can be used: (i) measurement of the spacing of the lightsources, (ii) determination of the location of the light sourcesrelative to the vehicle, and (iii) use of a red filter where thebrightness of the light source through the filter is compared with thebrightness of the unfiltered light. In the case of the taillight, thebrightness of the red filtered and unfiltered light is nearly the samewhile there is a significant difference for the headlight case. In thissituation, either two CCD arrays are used, one with a filter, or afilter which can be removed either electrically, such as with a liquidcrystal, or mechanically. Alternately a fast Fourier transform, or otherspectral analysis technique, of the data can be taken to determine therelative red content.

6. Weight Measurement and Biometrics

One way to determine motion of the occupant(s) is to monitor the weightdistribution of the occupant whereby changes in weight distributionafter an accident would be highly suggestive of movement of theoccupant. A system for determining the weight distribution of theoccupants can be integrated or otherwise arranged in the seats 3 and 4of the vehicle and several patents and publications describe suchsystems.

More generally, any sensor that determines the presence and health stateof an occupant can also be integrated into the vehicle interiormonitoring system in accordance with the inventions herein. For example,a sensitive motion sensor can determine whether an occupant is breathingand a chemical sensor, such as accomplished using SAW technology, candetermine the amount of carbon dioxide, or the concentration of carbondioxide, in the air in the vehicle, which can be correlated to thehealth state of the occupant(s). The motion sensor and chemical sensorcan be designed to have a fixed operational field situated near theoccupant. In the alternative, the motion sensor and chemical sensor canbe adjustable and adapted to adjust their operational field inconjunction with a determination by an occupant position and locationsensor that would determine the location of specific parts of theoccupant's body such as his or her chest or mouth. Furthermore, anoccupant position and location sensor can be used to determine thelocation of the occupant's eyes and determine whether the occupant isconscious, that is, whether his or her eyes are open or closed ormoving.

Chemical sensors can also be used to detect whether there is bloodpresent in the vehicle such as after an accident. Additionally,microphones can detect whether there is noise in the vehicle caused bygroaning, yelling, etc., and transmit any such noise through thecellular or similar connection to a remote listening facility using atelematics communication system such as operated by OnStar™.

FIG. 2A shows a schematic diagram of an embodiment of the inventionincluding a system for determining the presence and health state of anyoccupants of the vehicle and a telecommunications link. This embodimentincludes a system 150 for determining the presence of any occupants 151,which may take the form of a heartbeat sensor, chemical sensor or motionsensor as described above and a system for determining the health stateof any occupants 151. The latter system may be integrated into thesystem for determining the presence of any occupants using the same ordifferent component. The presence determining system 150 may encompass adedicated presence determination device associated with each seatinglocation in the vehicle, or at least sufficient presence determinationdevices having the ability to determine the presence of an occupant ateach seating location in the vehicle. Further, a system for determiningthe location, and optionally velocity, of the occupants or one or moreparts thereof 152 are provided and may be any conventional occupantposition sensor or preferably, one of the occupant position sensors asdescribed herein such as those utilizing waves such as electromagneticradiation or fields such as capacitance sensors or as described in thecurrent assignee's patents and patent applications as well as herein.

A processor 153 is coupled to the presence determining system 150, thehealth state determining system 151 and the location determining system152. A communications unit 154 is coupled to the processor 153. Theprocessor 153 and/or communications unit 154 can also be coupled tomicrophones 158 that can be distributed throughout the vehicle passengercompartment and include voice-processing circuitry to enable theoccupant(s) to effect vocal control of the processor 153, communicationsunit 154 or any coupled component or oral communications via thecommunications unit 154. The processor 153 is also coupled to anothervehicular system, component or subsystem 155 and can issue controlcommands to effect adjustment of the operating conditions of the system,component or subsystem. Such a system, component or subsystem can be theheating or air-conditioning system, the entertainment system, anoccupant restraint device such as an airbag, a glare prevention system,etc. Also, a positioning system 156, such as a GPS or differential GPSsystem, could be coupled to the processor 153 and provides an indicationof the absolute position of the vehicle.

Pressure or weight sensors 7, 76 are also included in the system shownin FIG. 6. Although strain gage-type sensors are schematicallyillustrated mounted to the supporting structure of the seat portion 4,and a bladder pressure sensor mounted in the seat portion 4, any othertype of pressure or weight sensor can be used including mat or buttspring sensors. Strain gage sensors are described in U.S. Pat. No.6,242,701 as well as herein. Weight can be used to confirm the occupancyof the seat, i.e., the presence or absence of an occupant as well aswhether the seat is occupied by a light or heavy object. In the lattercase, a measured weight of less than 60 pounds is often determinative ofthe presence of a child seat whereas a measured weight of greater than60 pounds is often indicative of the absence of a child seat. The weightsensors 7 can also be used to determine the weight distribution of theoccupant of the seat and thereby ascertain whether the occupant ismoving and the position of the occupant. As such, the weight sensors 7could be used to confirm the position and motion of the occupant. Themeasured pressure or weight or distribution thereof can also be used incombination with the data from the transmitter/receiver assemblies 49,50, 51, 52 and 54 of FIG. 8C to provide an identification of theoccupants in the seat.

Additional details about various weight sensing systems are set forth inthe '996 application, section 6, with reference to FIGS. 6A, 6B, 32, 33and 33A therein.

6.1 Strain Gage Weight Sensors

Strain gage and other weight sensors for use in embodiments of theinvention are shown in FIGS. 42-47 in the '934 application. Strain gageweight sensors can also be mounted in other locations such as within acavity within a seat cushion. The strain gage can be mounted on aflexible diaphragm that flexes and thereby strains the strain gage asthe seat is loaded.

6.2 Bladder Weight Sensors

One embodiment of a weight sensor and method for determining the weightof an occupant of a seat, which may be used in the methods and apparatusfor adjusting a vehicle component and identifying an occupant of a seat,comprises a bladder having at least one chamber adapted to be arrangedin a seat portion of the seat, and at least one transducer for measuringthe pressure in a respective chamber. The bladder may comprise aplurality of chambers, each adapted to be arranged at a differentlocation in the seat portion of the seat. Thus, it is possible todetermine the weight distribution of the occupant using this weightsensor with several transducers whereby each transducer is associatedwith one chamber and the weight distribution of the occupant is obtainedfrom the pressure measurements of the transducers. The position of theoccupant and the center of gravity of the occupant can also bedetermined by one skilled in the art based on the weight distribution.

With knowledge of the weight of an occupant, additional improvements canbe made to automobile and truck seat designs. In particular, thestiffness of the seat can be adjusted so as to provide the same level ofcomfort for light and for heavy occupants. The damping of occupantmotions, which previously has been largely neglected, can also bereadily adjusted as shown on FIG. 29 which is a view of the seat of FIG.28 showing one of several possible arrangements for changing thestiffness and the damping of the seat. In the seat bottom 250, there isa container 251, the conventional foam and spring design has beenreplaced by an inflated rectangular container very much like an airmattress which contains a cylindrical inner container 252 which isfilled with an open cell urethane foam, for example, or other meanswhich constrain the flow of air therein. An adjustable orifice 253connects the two containers both of which can be bladders 251, 252 sothat air, or other fluid, can flow in a controlled manner therebetween.The amount of opening of orifice 253 is controlled by control circuit254. A small air compressor, or fluid pump, 255 controls the pressure incontainer 251 under control of the control circuit 254. A pressuretransducer 256 monitors the pressure within container 251 and inputsthis information into control circuit 254.

The operation of the system is as follows. When an occupant sits on theseat, pressure initially builds up in the seat container or bladder 251which gives an accurate measurement of the weight of the occupant.Control circuit 254, using an algorithm and a microprocessor, thendetermines an appropriate stiffness for the seat and adds pressure toachieve that stiffness. The pressure equalizes between the twocontainers 251 and 252 through the flow of fluid through orifice 253.Control circuit 254 also determines an appropriate damping for theoccupant and adjusts the orifice 253 to achieve that damping. As thevehicle travels down the road and the road roughness causes the seat tomove up and down, the inertial force on the seat by the occupant causesthe fluid pressure to rise and fall in container 252 and also, but, muchless so, in container 251 since the occupant sits mainly above container252 and container 251 is much larger than container 252. The majordeflection in the seat takes place first in container 252 whichpressurizes and transfers fluid to container 251 through orifice 253.The size of the orifice opening determines the flow rate between the twocontainers 251, 252 and therefore the damping of the motion of theoccupant. Since this opening is controlled by control circuit 254, theamount of damping can thereby also be controlled. Thus, in this simplestructure, both the stiffness and damping can be controlled to optimizethe seat for a particular driver. If the driver does not like thesettings made by control circuit 254, he or she can change them toprovide a stiffer or softer ride. When fluid is used above, it can meana gas, liquid, gel or other flowable medium.

The stiffness of a seat is the change in force divided by the change indeflection. This is important for many reasons, one of which is that itcontrols the natural vibration frequency of the seat occupantcombination. It is important that this be different from the frequencyof vibrations which are transmitted to the seat from the vehicle inorder to minimize the up and down motions of the occupant. The dampingis a force which opposes the motion of the occupant and which isdependent on the velocity of relative motion between the occupant andthe seat bottom. It thus removes energy and minimizes the oscillatorymotion of the occupant. These factors are especially important in truckswhere the vibratory motions of the driver's seat, and thus the driver,have caused many serious back injuries among truck drivers.

In FIG. 29, the airbag or bladder 241 which interacts with the occupantis shown with a single chamber. Bladder 241 can be composed of multiplechambers 241 a, 241 b, 241 c, and 241 d as shown in FIG. 33A of the '934application. The use of multiple chambers permits the weightdistribution of the occupant to be determined if a separate pressuretransducer is used in each cell of the bladder, or if a single gage isswitched from chamber to chamber. Such a scheme gives the opportunity ofdetermining to some extent the position of the occupant on the seat orat least the position of the center of gravity of the occupant. Morethan four chambers can be used.

6.3 Combined Spatial and Weight

A novel occupant position sensor for a vehicle, for determining theposition of the occupant, comprises a weight sensor for determining theweight of an occupant of a seat and a processor for receiving thedetermined weight of the occupant from the weight sensor and determiningthe position of the occupant based at least in part on the determinedweight of the occupant. The position of the occupant could also bedetermined based in part on waves received from the space above theseat, data from seat position sensors, reclining angle sensors, etc.

Although spatial sensors such as ultrasonic, electric field and opticaloccupant sensors can accurately identify and determine the location ofan occupying item in the vehicle, a determination of the mass of theitem is less accurate as it can be fooled in some cases by a thick butlight winter coat, for example. Therefore, it is desirable, when theeconomics permit, to provide a combined system that includes both weightand spatial sensors. Such a system permits a fine tuning of thedeployment time and the amount of gas in the airbag to match theposition and the mass of the occupant. If this is coupled with a smartcrash severity sensor, then a true smart airbag system can result, asdisclosed in U.S. Pat. No. 6,532,408.

As disclosed in the current assignee's patents, the combination of areduced number of transducers including weight and spatial can resultfrom a pruning process starting from a larger number of sensors. Forexample, such a process can begin with four load cells and fourultrasonic sensors and after a pruning process, a system containing twoultrasonic sensors and one load cell can result. At least one of theinventions disclosed herein is therefore not limited to any particularnumber or combination of sensors and the optimum choice for a particularvehicle will depend on many factors including the specifications of thevehicle manufacturer, cost, accuracy desired, availability of mountinglocations and the chosen technologies.

6.4 Face Recognition

A neural network, or other pattern recognition system, can be trained torecognize certain people as permitted operators of a vehicle or forgranting access to a cargo container or truck trailer. In this case, ifa non-recognized person attempts to operate the vehicle or to gainaccess, the system can disable the vehicle and/or sound an alarm or senda message to a remote site via telematics. Since it is unlikely that anunauthorized operator will resemble the authorized operator, the neuralnetwork system can be quite tolerant of differences in appearance of theoperator. The system defaults to where a key or other identificationsystem must be used in the case that the system doesn't recognize theoperator or the owner wishes to allow another person to operate thevehicle or have access to the container. The transducers used toidentify the operator can be any of the types described herein. Apreferred method is to use optical imager-based transducers perhaps inconjunction with a weight sensor for automotive applications. This isnecessary due to the small size of the features that need to berecognized for a high accuracy of recognition. An alternate system usesan infrared laser, which can be modulated to provide three-dimensionalmeasurements, to irradiate or illuminate the operator and a CCD or CMOSdevice to receive the reflected image. In this case, the recognition ofthe operator is accomplished using a pattern recognition system such asdescribed in Popesco, V. and Vincent, J. M. “Location of Facial FeaturesUsing a Boltzmann Machine to Implement Geometric Constraints”, Chapter14 of Lisboa, P. J. G. and Taylor, M. J. Editors, Techniques andApplications of Neural Networks, Ellis Horwood Publishers, New York,1993. In the present case, a larger CCD element array containing 50,000or more elements would typically be used instead of the 16 by 16 or 256element CCD array used by Popesco and Vincent.

FIG. 18 shows a schematic illustration of a system for controllingoperation of a vehicle based on recognition of an authorized individualin accordance with the invention. A similar system can be designed forallowing access to a truck trailer, cargo container or railroad car, forexample. One or more images of the passenger compartment 260 arereceived at 261 and data derived therefrom at 262. Multiple imagereceivers may be provided at different locations. The data derivationmay entail any one or more of numerous types of image processingtechniques such as those described in U.S. Pat. No. 6,397,136 includingthose designed to improve the clarity of the image. A patternrecognition algorithm, e.g., a neural network, is trained in a trainingphase 263 to recognize authorized individuals. The training phase can beconducted upon purchase of the vehicle by the dealer or by the ownerafter performing certain procedures provided to the owner, e.g., entryof a security code or key or at another appropriate time and place. Inthe training phase for a theft prevention system, the authorizedoperator(s) would sit themselves in the passenger seat and opticalimages would be taken and processed to obtain the pattern recognitionalgorithm. Alternately, the training can be done away from the vehiclewhich would be more appropriate for cargo containers and the like.

A processor 264 is embodied with the pattern recognition algorithm thustrained to identify whether a person is the authorized individual byanalysis of subsequently obtained data derived from optical images 262.The pattern recognition algorithm in processor 264 outputs an indicationof whether the person in the image is an authorized individual for whichthe system is trained to identify. A security system 265 enablesoperations of the vehicle when the pattern recognition algorithmprovides an indication that the person is an individual authorized tooperate the vehicle and prevents operation of the vehicle when thepattern recognition algorithm does not provide an indication that theperson is an individual authorized to operate the vehicle.

In some cases, the recognition system can be substantially improved ifdifferent parts of the electromagnetic spectrum are used. As taught inthe book Alien Vision referenced above, distinctive facial markings areevident when viewed under near UV or MWIR illumination that can be usedto positively identify a person. Other biometric measures can be usedwith, or in place of, a facial or iris image to further improve therecognition accuracy such as voice recognition (voice-print), finger orhand prints, weight, height, arm length, hand size etc.

Instead of a security system, another component in the vehicle can beaffected or controlled based on the recognition of a particularindividual. For example, the rear view mirror, seat, seat belt anchoragepoint, headrest, pedals, steering wheel, entertainment system,air-conditioning/ventilation system can be adjusted. Additionally, thedoor can be unlocked upon approach of an authorized person.

FIG. 19 is a schematic illustration of a method for controllingoperation of a vehicle based on recognition of a person as one of a setof authorized individuals. Although the method is described and shownfor permitting or preventing ignition of the vehicle based onrecognition of an authorized driver, it can be used to control for anyvehicle component, system or subsystem based on recognition of anindividual.

Initially, the system is set in a training phase 266 in which images,and other biometric measures, including the authorized individuals areobtained by means of at least one optical receiving unit 267 and apattern recognition algorithm is trained based thereon 268, usuallyafter application of one or more image processing techniques to theimages. The authorized individual(s) occupy the passenger compartment,or some other appropriate location, and have their picture taken by theoptical receiving unit to enable the formation of a database on whichthe pattern recognition algorithm is trained. Training can be performedby any known method in the art, although combination neural networks arepreferred.

The system is then set in an operational phase 269 wherein an image isoperatively obtained 270, including the driver when the system is usedfor a security system. If the system is used for component adjustment,then the image would include any passengers or other occupying items inthe vehicle. The obtained image, or images if multiple optical receivingunits are used, plus other biometric information, are input into thepattern recognition algorithm 271, preferably after some imageprocessing, and a determination is made whether the pattern recognitionalgorithm indicates that the image includes an authorized driver 272. Ifso, ignition, or some other system, of the vehicle is enabled 273, orthe vehicle may actually be started automatically. If not, an alarm issounded and/or the police or other remote site may be contacted 274.

Once an optic-based system is present in a vehicle, other options can beenabled such as eye-tracking as a data input device or to detectdrowsiness, as discussed above, and even lip reading as a data inputdevice or to augment voice input. This is discussed, for example,Eisenberg, Anne, “Beyond Voice Recognition to a Computer That ReadsLips”, New York Times, Sep. 11, 2003. Lip reading can be implemented ina vehicle through the use of IR illumination and training of a patternrecognition algorithm, such as a neural network or a combinationnetwork. This is one example of where an adaptive neural or combinationnetwork can be employed that learns as it gains experience with aparticular driver. The word “radio”, for example, can be associated withlip motions when the vehicle is stopped or moving slowly and then at alater time when the vehicle is traveling at high speed with considerablewind noise, the voice might be difficult for the system to understand.When augmented with lip reading, the word “radio” can be more accuratelyrecognized. Thus, the combination of lip reading and voice recognitioncan work together to significantly improve accuracy.

Face recognition can of course be done in two or three dimensions andcan involve the creation of a model of the person's head that can aidwhen illumination is poor, for example. Three dimensions are availableif multiple two dimensional images are acquired as the occupant moveshis or her head or through the use of a three-dimensional camera. Athree-dimensional camera generally has two spaced-apart lenses plussoftware to combine the two views. Normally, the lenses are relativelyclose together but this may not need to be the case and significantlymore information can be acquired if the lenses are spaced further apartand in some cases, even such that one camera has a frontal view and theother a side view, for example. The software is complicated for suchcases but the system becomes more robust and less likely to be blockedby a newspaper, for example. A scanning laser radar, PMD or similarsystem with a modulated beam or with range gating as described above canalso be used to obtain three-dimensional information or a 3D image.

Eye tracking as disclosed in Jacob, “Eye Tracking in Advanced InterfaceDesign”, Robert J. K. Jacob, Human-Computer Interaction Lab, NavalResearch Laboratory, Washington, D.C, can be used by vehicle operator tocontrol various vehicle components such as the turn signal, lights,radio, air conditioning, telephone, Internet interactive commands, etc.much as described in U.S. Pat. No. 7,126,583. The display used for theeye tracker can be a heads-up display reflected from the windshield orit can be a plastic electronics display located either in the visor orthe windshield.

The eye tracker works most effectively in dim light where the driver'seyes are sufficiently open that the cornea and retina are clearlydistinguishable. The direction of operator's gaze is determined bycalculation of the center of pupil and the center of the iris that arefound by illuminating the eye with infrared radiation. FIG. 8Eillustrates a suitable arrangement for illuminating eye along the sameaxis as the pupil camera. The location of occupant's eyes must be firstdetermined as described herein before eye tracking can be implemented.In FIG. 8E, imager system 52, 54, or 56 are candidate locations for eyetracker hardware.

The technique is to shine a collimated beam of infrared light on to beoperator's eyeball producing a bright corneal reflection can be brightpupil reflection. Imaging software analyzes the image to identify thelarge bright circle that is the pupil and a still brighter dot which isthe corneal reflection and computes the center of each of these objects.The line of the gaze is determined by connecting the centers of thesetwo reflections.

It is usually necessary only to track a single eye as both eyes tend tolook at the same object. In fact, by checking that both eyes are lookingat the same object, many errors caused by the occupant looking throughthe display onto the road or surrounding environment can be eliminated

Object selection with a mouse or mouse pad, as disclosed in U.S. Pat.No. 7,126,583, is accomplished by pointing at the object and depressinga button. Using eye tracking, an additional technique is available basedon the length of time the operator gazes at the object. In theimplementations herein, both techniques are available. In the simulatedmouse case, the operator gazes at an object, such as the airconditioning control, and depresses a button on the steering wheel, forexample, to select the object. Alternately, the operator merely gazes atthe object for perhaps one-half second and the object is automaticallyselected. Both techniques can be implemented simultaneously allowing theoperator to freely choose between them. The dwell time can be selectableby the operator as an additional option. Typically, the dwell times willrange from about 0.1 seconds to about 1 second.

The problem of finding the eyes and tracking the head of the driver, forexample, is handled in Smeraldi, F., Carmona, J. B., “Saccadic searchwith Garbor features applied to eye detection and real-time headtracking”, Image and Vision Computing 18 (2000) 323-329, ElsevierScience B.V. The Saccadic system described is a very efficient method oflocating the most distinctive part of a persons face, the eyes, and inaddition to finding the eyes, a modification of the system can be usedto recognize the driver. The system makes use of the motion of thesubject's head to locate the head prior to doing a search for the eyesusing a modified Garbor decomposition method. By comparing twoconsecutive frames, the head can usually be located if it is in thefield of view of the camera. Although this is the preferred method,other eye location and tracking methods can also be used as reported inthe literature and familiar to those skilled in the art.

6.5 Heartbeat and Health State

In addition to the use of transducers to determine the presence andlocation of occupants in a vehicle, other sensors can also be used. Forexample, as discussed above, a heartbeat sensor, which determines thenumber and presence of heartbeats, can also be arranged in the vehicle.Heartbeat sensors can be adapted to differentiate between a heartbeat ofan adult, a heartbeat of a child and a heartbeat of an animal. As itsname implies, a heartbeat sensor detects a heartbeat, and the magnitudethereof, of a human occupant of the seat or other position, if such ahuman occupant is present. The output of the heartbeat sensor is inputto the processor of the interior monitoring system. One heartbeat sensorfor use in the invention may be of the types as disclosed in McEwan inU.S. Pat. Nos. 5,573,012 and 5,766,208. The heartbeat sensor can bepositioned at any convenient position relative to the seats or otherappropriate location where occupancy is being monitored. A preferredautomotive location is within the vehicle seatback.

This type of micropower impulse radar (MIR) sensor is not believed tohave been used in an interior monitoring system in the past. It can beused to determine the motion of an occupant and thus can determine hisor her heartbeat (as evidenced by motion of the chest), for example.Such an MIR sensor can also be arranged to detect motion in a particulararea in which the occupant's chest would most likely be situated orcould be coupled to an arrangement which determines the location of theoccupant's chest and then adjusts the operational field of the MIRsensor based on the determined location of the occupant's chest. Amotion sensor utilizing a micro-power impulse radar (MIR) system asdisclosed, for example, in U.S. Pat. No. 5,361,070, as well as manyother patents by the same inventor. Motion sensing is accomplished bymonitoring a particular range from the sensor as disclosed in thatpatent. MIR is one form of radar that has applicability to occupantsensing and can be mounted at various locations in the vehicle.

Other forms include, among others, ultra wideband (UWB) by the TimeDomain Corporation and noise radar (NR) by Professor Konstantin Lukin ofthe National Academy of Sciences of Ukraine Institute of Radiophysicsand Electronics. Radar has an advantage over ultrasonic sensors in thatdata can be acquired at a higher speed and thus the motion of anoccupant can be more easily tracked. The ability to obtain returns overthe entire occupancy range is somewhat more difficult than withultrasound resulting in a more expensive system overall. MIR, UWB or NRhave additional advantages in their lack of sensitivity to temperaturevariation and have a comparable resolution to about 40 kHz ultrasound.Resolution comparable to higher frequency is of course possible usingmillimeter waves, for example. Additionally, multiple MIR, UWB or NRsensors can be used when high-speed tracking of the motion of anoccupant during a crash is required since they can be individuallypulsed without interfering with each other through frequency, time orcode division multiplexing or other multiplexing schemes.

Other methods have been reported for measuring heartbeat includingvibrations introduced into a vehicle and variations in the electricfield in the vicinity of where an occupant might reside. All suchmethods are considered encompassed by the teachings of at least one ofthe inventions disclosed herein. The detection of a heartbeat regardlessof how it is accomplished is indicative of the presence of a livingbeing within the vehicle and such a detection as part of an occupantpresence detection system is novel to at least one of the inventionsdisclosed herein. Similarly, any motion of an object that is not inducedby the motion of the vehicle itself is indicative of the presence of aliving being and thus part of the teachings herein. The sensing ofoccupant motion regardless of how it is accomplished when used in asystem to affect another vehicle system is contemplated herein.

6.6 Other Inputs

Information can be provided as to the location of the driver, or othervehicle occupant, relative to an airbag, to appropriate circuitry whichwill process this information and make a decision as to whether toprevent deployment of the airbag in a situation where it would otherwisebe deployed, or otherwise affect the time of deployment, rate ofinflation, rate of deflation etc. This information includes the positionof the seat and the spool out length of a seatbelt as discussed in the'996 application, section 6.6 with reference to FIGS. 14 and 15.

7. Illumination

7.1 Infrared Light

Many forms of illumination can of course be used. Near infrared is apreferred source since it can be produced relatively inexpensively withLEDs and is not seen by vehicle occupants or others outside of thevehicle. The use of spatially modulated (as in structured light) andtemporally modulated (as in amplitude, frequency, pulse, code, random orother such methods) permits additional information to be obtained suchas a three-dimensional image as disclosed by the current assignee inearlier patents. Infrared is also interesting since the human bodynaturally emits IR and this fact can be used to positively identify thatthere is a human occupying a vehicle seat and to determine fairlyaccurately the size of the occupant. This technique only works when theambient temperature is different from body temperature, which is most ofthe time. In some climates, it is possible that the interior temperatureof a vehicle can reach or exceed 100° F., but it is unlikely to stay atthat temperature for long as humans find such a temperatureuncomfortable. However, it is even more unlikely that such a temperaturewill exist except when there is significant natural illumination in thevisible part of the spectrum. Thus, a visual size determination ispossible especially since it is very unlikely that such an occupant willbe wearing heavy or thick clothing. Passive infrared, used of coursewith an imaging system, is thus a viable technique for theidentification of a human occupant if used in conjunction with anoptical system for high temperature situations. Even if the ambienttemperature is nearly the same as body temperature, there will still becontrasts in the image which are sufficient to differentiate an occupantor his or her face from the background. Whereas a single pixel sensor,as in prior art patents to Corrado and Mattes, could give false results,an imaging system such as a focal plane array as disclosed herein canstill operate effectively.

Passive IR is also a good method of finding the eyes and other featuresof the occupant since hair, some hats and other obscuring itemsfrequently do not interfere with the transmission of IR. When active IRillumination is used, the eyes are particularly easy to find due tocorneal reflection and the eyes will be dilated at night when findingthe eyes is most important. Even in glare situations, where the glare iscoming through the windshield, passive IR is particularly useful sinceglass blocks most IR with wavelengths beyond 1.1 microns and thus theglare will not interfere with the imaging of the face.

Particular frequencies of active IR are especially useful for externalmonitoring. Except for monitoring objects close to the vehicle, mostradar systems have a significant divergence angle making imaging morethan a few meters from the vehicle problematic. Thus there is typicallynot enough information from a scene say 100 meters away to permit themonitor to obtain an image that would permit classification of sensedobjects. Using radar, it is difficult to distinguish a car from a truckor a parked car at the side of the road from one on the same lane as thevehicle or from an advertising sign, for example. Normal visual imagingalso will not work in bad weather situations however some frequencies ofIR do penetrate fog, rain and snow sufficiently well as to permit themonitoring of the road at a significant distance and with enoughresolution to permit imaging and thus classification even in thepresence of rain, snow and fog.

As mentioned herein, there are various methods of illuminating theobject or occupant in the passenger compartment. A scanning point of IRcan be used to overcome reflected sunlight. A structured pattern can beused to help achieve a three-dimensional representation of the vehiclecontents. An image can be compared with illumination and without in anattempt to eliminate the effects on natural and uncontrollableillumination. This generally doesn't work very well since the naturalillumination can overpower the IR. Thus it is usually better to developtwo pattern recognition algorithms, one for IR illumination and one fornatural illumination. For the natural illumination case, the entirevisual and near visual spectrum can be used or some subset of it. Forthe case where a rolling shutter is used, the process can be speeded upsubstantially if one line of pixels is subtracted from the adjacent linewhere the illumination is turned on for every other row and off for theintervening rows. In addition to structured light, there are many othermethods of obtaining a 3D image as discussed above.

7.2 Structured Light

In the applications discussed and illustrated above, the source andreceiver of the electromagnetic radiation have frequently been mountedin the same package. This is not necessary and in some implementations,the illumination source will be mounted elsewhere. For example, a laserbeam can be used which is directed along an axis which bisects the anglebetween the center of the seat volume, or other volume of interest, andtwo of the arrays. Such a beam may come from the A-Pillar, for example.The beam, which may be supplemental to the main illumination system,provides a point reflection from the occupying item that, in most cases,can be seen by two receivers, even if they are significantly separatedfrom each other, making it easier to identify corresponding parts in thetwo images. Triangulation thereafter can precisely determination thelocation of the illuminated point. This point can be moved, or a patternof points provided, to provide even more information. In another casewhere it is desired to track the head of the occupant, for example,several such beams can be directed at the occupant's head duringpre-crash braking or even during a crash to provide the fastestinformation as to the location of the head of the occupant for thefastest tracking of the motion of the occupant's head. Since only a fewpixels are involved, even the calculation time is minimized.

In most of the applications above, the assumption has been made thateither a uniform field of light or a scanning spot of light will beprovided. This need not be the case. The light that is emitted ortransmitted to illuminate the object can be structured light. Structuredlight can take many forms starting with, for example, a rectangular orother macroscopic pattern of light and dark that can be superimposed onthe light by passing it through a filter. If a similar pattern isinterposed between the reflections and the camera, a sort ofpseudo-interference pattern can result sometimes known as Moirépatterns. A similar effect can be achieved by polarizing transmittedlight so that different parts of the object that is being illuminatedare illuminated with light of different polarization. Once again, byviewing the reflections through a similarly polarized array, informationcan be obtained as to where the source of light came from which isilluminating a particular object. Any of the transmitter/receiverassemblies or transducers in any of the embodiments above using opticscan be designed to use structured light.

Usually the source of the structured light is displaced eithervertically, laterally or axially from the imager, but this need notnecessarily be the case. One excellent example of the use of structuredlight to determine a 3D image where the source of the structured lightand the imager are on the same axis is illustrated in U.S. Pat. No.5,003,166. Here, the third dimension is obtained by measuring the degreeof blur of the pattern as reflected from the object. This can be donesince the focal point of the structured light is different from thecamera. This is accomplished by projecting it through its own lenssystem and then combining the two paths through the use of a beamsplitter. The use of this or any other form of structured light iswithin the scope of at least one of the inventions disclosed herein.There are so many methods that the details of all of them cannot beenumerated here.

One consideration when using structured light is that the source ofstructured light should not generally be exactly co-located with thearray because in this case, the pattern projected will not change as afunction of the distance between the array and the object and thus thedistance between the array and the object cannot be determined, exceptby the out-of-focus and similar methods discussed above. Thus, it isusually necessary to provide a displacement between the array and thelight source. For example, the light source can surround the array, beon top of the array or on one side of the array. The light source canalso have a different virtual source, i.e., it can appear to come frombehind of the array or in front of the array, a variation of theout-of-focus method discussed above.

For a laterally displaced source of structured light, the goal is todetermine the direction that a particular ray of light had when it wastransmitted from the source. Then, by knowing which pixels wereilluminated by the reflected light ray along with the geometry of thevehicle, the distance to the point of reflection off of the object canbe determined. If a particular light ray, for example, illuminates anobject surface which is near to the source, then the reflection off ofthat surface will illuminate a pixel at a particular point on theimaging array. If the reflection of the same ray however occurs from amore distant surface, then a different pixel will be illuminated in theimaging array. In this manner, the distance from the surface of theobject to the array can be determined by triangulation formulas.Similarly, if a given pixel is illuminated in the imager from areflection of a particular ray of light from the transmitter, andknowing the direction that that ray of light was sent from thetransmitter, then the distance to the object at the point of reflectioncan be determined. If each ray of light is individually recognizable andtherefore can be correlated to the angle at which it was transmitted, afull three-dimensional image can be obtained of the object thatsimplifies the identification problem. This can be done with a singleimager.

One particularly interesting implementation due to its low cost is toproject one or more dots or other simple shapes onto the occupant from aposition which is at an angle relative to the occupant such as 10 to 45degrees from the camera location. These dots will show up as brightspots even in bright sunlight and their location on the image willpermit the position of the occupant to be determined. Since the parts ofthe occupant are all connected with relative accuracy, the position ofthe occupant can now be accurately determined using only one simplecamera. Additionally, the light that makes up the dots can be modulatedand the distance from the dot source can then be determined if there isa receiver at the light source and appropriate circuitry such as usedwith a scanning range meter.

The coding of the light rays coming from the transmitter can beaccomplished in many ways. One method is to polarize the light bypassing the light through a filter whereby the polarization is acombination of the amount and angle of the polarization. This gives twodimensions that can therefore be used to fix the angle that the lightwas sent. Another method is to superimpose an analog or digital signalonto the light which could be done, for example, by using an addressablelight valve, such as a liquid crystal filter, electrochromic filter, or,preferably, a garnet crystal array. Each pixel in this array would becoded such that it could be identified at the imager or other receivingdevice. Any of the modulation schemes could be applied such asfrequency, phase, amplitude, pulse, random or code modulation.

The techniques described above can depend upon either changing thepolarization or using the time, spatial or frequency domains to identifyparticular transmission angles with particular reflections. Spatialpatterns can be imposed on the transmitted light which generally goesunder the heading of structured light. The concept is that if a patternis identifiable, then either the direction of transmitted light can bedetermined or, if the transmission source is co-linear with thereceiver, then the pattern differentially expands or contracts relativeto the field of view as it travels toward the object and then, bydetermining the size or focus of the received pattern, the distance tothe object can be determined. In some cases, Moiré pattern techniquesare utilized.

When the illumination source is not placed on the same axis as thereceiving array, it is typically placed at an angle such as 45 degrees.At least two other techniques can be considered. One is to place theillumination source at 90 degrees to the imager array. In this case,only those surface elements that are closer to the receiving array thanprevious surfaces are illuminated. Thus, significant information can beobtained as to the profile of the object. In fact, if no object isoccupying the seat, then there will be no reflections except from theseat itself. This provides a very powerful technique for determiningwhether the seat is occupied and where the initial surfaces of theoccupying item are located. A combination of the above techniques can beused with temporally or spatially varying illumination. Taking imageswith the same imager but with illumination from different directions canalso greatly enhance the ability to obtain three-dimensionalinformation.

The particular radiation field of the transmitting transducer can alsobe important to some implementations of at least one of the inventionsdisclosed herein. In some techniques, the object which is occupying theseat is the only part of the vehicle which is illuminated. Extreme careis exercised in shaping the field of light such that this is true. Forexample, the objects are illuminated in such a way that reflections fromthe door panel do not occur. Ideally, if only the items which occupy theseat can be illuminated, then the problem of separating the occupantfrom the interior vehicle passenger compartment surfaces can be moreeasily accomplished. Sending illumination from both sides of the vehicleacross the vehicle can accomplish this.

The above discussion has concentrated on automobile occupant sensing butthe teachings, with some modifications, are applicable to monitoring ofother vehicles including railroad cars, truck trailers and cargocontainers.

7.3 Color and Natural Light

As discussed above, the use of multispectral imaging can be asignificant aid in recognizing objects inside and outside of a vehicle.Two objects may not be separable under monochromic illumination yet bequite distinguishable when observed in color or with illumination fromother parts of the electromagnetic spectrum. Also, the identification ofa particular individual is enhanced using near UV radiation, forexample. Even low level X-rays can be useful in identifying and locatingobjects in a vehicle.

7.4 Radar

Particular mention should be made of the use of radar since novelinexpensive antennas and ultra wideband radars are now readilyavailable. A scanning radar beam can be used in this implementation andthe reflected signal is received by a phase array antenna to generate animage of the occupant for input into the appropriate pattern detectioncircuitry. The image is not very clear due to the longer wave lengthsused and the difficulty in getting a small enough radar beam. The wordcircuitry as used herein includes, in addition to normal electroniccircuits, a microprocessor and appropriate software.

Another preferred embodiment makes use of radio waves and avoltage-controlled oscillator (VCO). In this embodiment, the frequencyof the oscillator is controlled through the use of a phase detectorwhich adjusts the oscillator frequency so that exactly one half waveoccupies the distance from the transmitter to the receiver viareflection off of the occupant. The adjusted frequency is thus inverselyproportional to the distance from the transmitter to the occupant.Alternately, an FM phase discriminator can be used as known to thoseskilled in the art. These systems could be used in any of the locationsillustrated in FIG. 5 as well as in the monitoring of other vehicletypes.

In FIG. 6, a motion sensor 73 is arranged to detect motion of anoccupying item on the seat 4 and the output thereof is input to theneural network 65. Motion sensors can utilize a micro-power impulseradar (MIR) system as disclosed, for example, in McEwan U.S. Pat. No.5,361,070, as well as many other patents by the same inventor. Motionsensing is accomplished by monitoring a particular range from the sensoras disclosed in that patent. MIR is one form of radar which hasapplicability to occupant sensing and can be mounted, for example, atlocations such as designated by reference numerals 6 and 8-10 in FIG. 7.It has an advantage over ultrasonic sensors in that data can be acquiredat a higher speed and thus the motion of an occupant can be more easilytracked. The ability to obtain returns over the entire occupancy rangeis somewhat more difficult than with ultrasound resulting in a moreexpensive system overall. MIR has additional advantages over ultrasoundin lack of sensitivity to temperature variation and has a comparableresolution to about 40 kHz ultrasound. Resolution comparable to higherfrequency is feasible but has not been demonstrated. Additionally,multiple MIR sensors can be used when high speed tracking of the motionof an occupant during a crash is required since they can be individuallypulsed without interfering with each, through time divisionmultiplexing. MIR sensors are also particularly applicable to themonitoring of other vehicles and can be configured to provide a systemthat requires very low power and thus is ideal for use withbattery-operated systems that require a very long life.

Sensors 126, 127, 128, 129 in FIG. 24 can also be microwave or mm waveradar sensors which transmit and receive radar waves. As such, it ispossible to determine the presence of an object in the rear seat and thedistance between the object and the sensors. Using multiple radarsensors, it would be possible to determine the contour of an object inthe rear seat and thus using pattern recognition techniques, theclassification or identification of the object. Motion of objects in therear seat can also be determined using radar sensors. For example, ifthe radar sensors are directed toward a particular area and/or areprovided with the ability to detect motion in a predetermined frequencyrange, they can be used to determine the presence of children or petsleft in the vehicle, i.e., by detecting heartbeats or other body motionssuch as movement of the chest cavity.

7.5 Frequency or Spectrum Considerations

The maximum acoustic frequency range that is practical to use foracoustic imaging in the acoustic systems herein is about 40 to 160kilohertz (kHz). The wavelength of a 50 kHz acoustic wave is about 0.6cm, which is too coarse to determine the fine features of a person'sface, for example. It is well understood by those skilled in the artthat features that are smaller than the wavelength of the irradiatingradiation cannot be distinguished. Similarly, the wavelength of commonradar systems varies from about 0.9 cm (for 33 GHz K band) to 133 cm(for 225 MHz P band), which is also too coarse for person identificationsystems. Millimeter wave and sub-millimeter wave radar can of courseemit and receive waves considerably smaller. Millimeter wave radar andMicropower Impulse Radar (MIR) as discussed above are particularlyuseful for occupant detection and especially the motion of occupantssuch as motion caused by heartbeats and breathing, but still too coursefor feature identification. For security purposes, for example, MIR canbe used to detect the presence of weapons on a person that might beapproaching a vehicle such as a bus, truck or train and thus provide awarning of a potential terrorist threat. Passive IR is also useful forthis purpose.

MIR is reflected by edges, joints and boundaries and through thetechnique of range gating, particular slices in space can be observed.Millimeter wave radar, particularly in the passive mode, can also beused to locate life forms because they naturally emit waves atparticular wave lengths such as 3 mm. A passive image of such a personwill also show the presence of concealed weapons as they block thisradiation. Similarly, active millimeter wave radar reflects off ofmetallic objects but is absorbed by the water in a life form. Theabsorption property can be used by placing a radar receiver or reflectorbehind the occupant and measuring the shadow caused by the absorption.The reflective property of weapons including plastics can be used asabove to detect possible terrorist threats. Finally, the use ofsub-millimeter waves again using a detector or reflector on the otherside of the occupant can be used not only to determine the density ofthe occupant but also some measure of its chemical composition as thechemical properties alter the pulse shape. Such waves are more readilyabsorbed by water than by plastic. From the above discussion, it can beseen that there are advantages of using different frequencies of radarfor different purposes and, in some cases, a combination of frequenciesis most useful. This combination occurs naturally with noise radar (NR),ultra-wideband radar (UWB) and MIR and these technologies are mostappropriate for occupant detection when using electromagnetic radiationat longer wavelengths than visible light and IR.

Another variant on the invention is to use no illumination source atall. In this case, the entire visible and infrared spectrum could beused. CMOS arrays are now available with very good night visioncapabilities making it possible to see and image an occupant in very lowlight conditions. QWIP, as discussed above, may someday become availablewhen on-chip cooling systems using a dual stage Peltier system becomecost effective or when the operating temperature of the device risesthrough technological innovation. For a comprehensive introduction tomultispectral imaging, see Richards, Austin Alien Vision, Exploring theElectromagnetic Spectrum with Imaging Technology, SPIE Press, 2001.

Thus many different frequencies can be used to image a scene each havingparticular advantages and disadvantages. At least one of the inventionsdisclosed herein is not limited to using a particular frequency or partof the electromagnetic spectrum and images can advantageously becombined from different frequencies. For example, a radar image can becombined or fused with an image from the infrared or ultravioletportions of the spectrum. Additionally, the use of a swept frequencyrange such as in a chirp can be advantageously used to distinguishdifferent objects or in some cases different materials. It is well knownthat different materials absorb and reflect different electromagneticwaves and that this fact can be used to identify the material as inspectrographic analysis.

8. Field Sensors and Antennas

A living object such as an animal or human has a fairly high electricalpermittivity (Dielectric Constant) and relatively lossy dielectricproperties (Loss Tangent) absorbs a lot of energy absorption when placedin an appropriate varying electric field. This effect varies with thefrequency. If a human, which is a lossy dielectric, is present in thedetection field, then the dielectric absorption causes the value of thecapacitance of the object to change with frequency. For a human (poordielectric) with high dielectric losses (loss tangent), the decay withfrequency will be more pronounced than objects that do not present thishigh loss tangency. Exploiting this phenomena, it is possible to detectthe presence of an adult, child, baby or pet that is in the field of thedetection circuit.

In FIG. 6, a capacitive sensor 78 is arranged to detect the presence ofan occupying item on the seat 4 and the output thereof is input to theneural network 65. Capacitive sensors can be located many other placesin the passenger compartment. Capacitive sensors appropriate for thisfunction are disclosed in U.S. Pat. Nos. 5,602,734, 5,802,479, 5,844,486and 5,948,031. Capacitive sensors can in general be mounted at locationsdesignated by reference numerals 6 and 8-10 in FIG. 7 or as shown inFIG. 6 or in the vehicle seat and seatback, although by their naturethey can occupy considerably more space than shown in the drawings.

In FIG. 4, transducers 5, 11, 12, 13, 14 and 15 can be antennas placedin the seat and headrest such that the presence of an object,particularly a water-containing object such as a human, disturbs thenear field of the antenna. This disturbance can be detected by variousmeans such as with Micrel parts MICREF102 and MICREF104, which have abuilt-in antenna auto-tune circuit. Note, these parts cannot be used asis and it is necessary to redesign the chips to allow the auto-tuneinformation to be retrieved from the chip.

Note that the bio-impedance that can be measured using the methodsdescribed above can be used to obtain a measure of the water mass, forexample, of an object and thus of its weight.

9. Telematics

Some of the inventions herein relate generally to telematics and thetransmission of information from a vehicle to one or more remote siteswhich can react to the position or status of the vehicle and/oroccupant(s) therein.

For example, the cellular phone system, or other telematicscommunication device, is shown schematically in FIG. 2 by box 34 andoutputs to an antenna 32. The phone system or telematics communicationdevice 34 can be coupled to the vehicle interior monitoring system inaccordance with any of the embodiments disclosed herein and serves toestablish a communications channel with one or more remote assistancefacilities, such as an EMS facility or dispatch facility from whichemergency response personnel are dispatched. The telematics system canalso be a satellite-based system such as provided by Skybitz.

Additional details about this aspect of the invention are found in the'996 application, section 9.

10. Display

A portion of the windshield, such as the lower left corner, can be usedto display the vehicle and surrounding vehicles or other objects as seenfrom above, for example, as described in U.S. Pat. No. 7,049,945. Thisdisplay can use pictures or icons as appropriate. In another case, thecondition of the road such as the presence, or likelihood of black icecan be displayed on the windshield where it would show on the road ifthe driver could see it. This would require a source of information thatsuch a condition exists, however, here the concern is that it can bedisplayed whatever the source of this or any other relevant information.When used in conjunction with a navigation system, directions includingpointing arrows or a path outline perhaps in color, similar to the firstdown line on a football field as seen on TV, can be displayed to directthe driver to his destination or to points of interest.

11. Pattern Recognition

In basic embodiments of the inventions, wave or energy-receivingtransducers are arranged in the vehicle at appropriate locations,associated algorithms are trained, if necessary depending on theparticular embodiment, and function to determine whether a life form, orother object, is present in the vehicle and if so, how many life formsor objects are present. A determination can also be made using thetransducers as to whether the life forms are humans, or morespecifically, adults, child in child seats, etc. As noted above andbelow, this is possible using pattern recognition techniques. Moreover,the processor or processors associated with the transducers can betrained (loaded with a trained pattern recognition algorithm) todetermine the location of the life forms or objects, either periodicallyor continuously or possibly only immediately before, during and after acrash. The location of the life forms or objects can be as general or asspecific as necessary depending on the system requirements, i.e., adetermination can be made that a human is situated on the driver's seatin a normal position (general) or a determination can be made that ahuman is situated on the driver's seat and is leaning forward and/or tothe side at a specific angle as well as determining the position of hisor her extremities and head and chest (specific). Or, a determinationcan be made as to the size or type of objects such as boxes are in atruck trailer or cargo container. The degree of detail is limited byseveral factors, including, e.g., the number, position and type oftransducers and the training of the pattern recognition algorithm.

When different objects are placed on the front passenger seat, theimages (here “image” is used to represent any form of signal) fromtransducers 6, 8, 10 (FIG. 1) are different for different objects butthere are also similarities between all images of rear facing childseats, for example, regardless of where on the vehicle seat it is placedand regardless of what company manufactured the child seat. Alternately,there will be similarities between all images of people sitting on theseat regardless of what they are wearing, their age or size. The problemis to find the set of “rules” or an algorithm that differentiates theimages of one type of object from the images of other types of objects,for example which differentiate the adult occupant images from the rearfacing child seat images or boxes. The similarities of these images forvarious child seats are frequently not obvious to a person looking atplots of the time series from ultrasonic sensors, for example, and thuscomputer algorithms are developed to sort out the various patterns. Fora more detailed discussion of pattern recognition see U.S. RE No. 37260.

The determination of these rules is important to the pattern recognitiontechniques used in at least one of the inventions disclosed herein. Ingeneral, three approaches have been useful, artificial intelligence,fuzzy logic and artificial neural networks including modular orcombination neural networks. Other types of pattern recognitiontechniques may also be used, such as sensor fusion as disclosed in U.S.Pat. Nos. 5,482,314, 5,890,085, and 6,249,729. In some of the inventionsdisclosed herein, such as the determination that there is an object inthe path of a closing window or door using acoustics or optics asdescribed herein, the rules are sufficiently obvious that a trainedresearcher can look at the returned signals and devise an algorithm tomake the required determinations. In others, such as the determinationof the presence of a rear facing child seat or of an occupant,artificial neural networks are used to determine the rules. Neuralnetwork software for determining the pattern recognition rules isavailable from various sources such as International ScientificResearch, Inc., Panama City, Panama.

The human mind has little problem recognizing faces even when they arepartially occluded such as with a hat, sunglasses or a scarf, forexample. With the increase in low cost computing power, it is nowbecoming possible to train a rather large neural network, perhaps acombination neural network, to recognize most of those cases where ahuman mind will also be successful.

Other techniques which may or may not be part of the process ofdesigning a system for a particular application include the following:

1. Fuzzy logic. Neural networks frequently exhibit the property thatwhen presented with a situation that is totally different from anypreviously encountered, an irrational decision can result. Frequently,when the trained observer looks at input data, certain boundaries to thedata become evident and cases that fall outside of those boundaries areindicative of either corrupted data or data from a totally unexpectedsituation. It is sometimes desirable for the system designer to addrules to handle these cases. These can be fuzzy logic-based rules orrules based on human intelligence. One example would be that whencertain parts of the data vector fall outside of expected bounds thatthe system defaults to an airbag-enable state or the previouslydetermined state.

2. Genetic algorithms. When developing a neural network algorithm for aparticular vehicle, there is no guarantee that the best of all possiblealgorithms has been selected. One method of improving the probabilitythat the best algorithm has been selected is to incorporate some of theprinciples of genetic algorithms. In one application of this theory, thenetwork architecture and/or the node weights are varied pseudo-randomlyto attempt to find other combinations which have higher success rates.The discussion of such genetic algorithms systems appears in the bookComputational Intelligence referenced above.

Although neural networks are preferred other classifiers such asBayesian classifiers can be used as well as any other patternrecognition system. A key feature of most of the inventions disclosedherein is the recognition that the technology of pattern recognitionrather than deterministic mathematics should be applied to solving theoccupant sensing problem.

11.1 Neural Networks

An occupant can move from a position safely displaced from the airbag toa position where he or she can be seriously injured by the deployment ofan airbag within a fraction of a second during pre-crash braking, forexample. On the other hand, it takes a substantially longer time periodto change the seat occupancy state from a forward facing person to arear facing child seat, or even from a forward facing child seat to arear facing child seat. This fact can be used in the discriminationprocess through post-processing algorithms. One method, which alsoprepares for DOOP, is to use a two-layered neural network or twoseparate neural networks. The first one categorizes the seat occupancyinto, for example, (1) empty seat, (2) rear facing child seat, (3)forward facing child seat and (4) forward facing human (not in a childseat). The second is used for occupant position determination. In theimplementation, the same input layer can be used for both neuralnetworks but separate hidden and output layers are used. This isillustrated in FIG. 187 of the '881 application which is similar to FIG.15B with the addition of a post processing operation for both thecategorization and position networks and the separate hidden layer nodesfor each network.

If the categorization network determines that either a category (3) or(4) exists, then the second network is run, which determines thelocation of the occupant. Significant averaging of the vectors is usedfor the first network and substantial evidence is required before theoccupancy class is changed. For example, if data is acquired every 10milliseconds, the first network might be designed to require 600 out of1000 changed vectors before a change of state is determined. In thiscase, at least 6 seconds of confirming data would be required. Such asystem would therefore not be fooled by a momentary placement of anewspaper by a forward facing human, for example, that might look like arear-facing child seat.

If, on the other hand, a forward facing human were chosen, his or herposition could be determined every 10 milliseconds. A decision that theoccupant had moved out of position would not necessarily be made fromone 10 millisecond reading unless that reading was consistent withprevious readings. Nevertheless, a series of consistent readings wouldlead to a decision within 10 milliseconds of when the occupant crossedover into the danger zone proximate to the airbag module. This method ofusing history is used to eliminate the effects of temperature gradients,for example, or other events that could temporarily distort one or morevectors. The algorithms which perform this analysis are part of thepost-processor.

More particularly, in one embodiment of the method in accordance with atleast one of the inventions herein in which two neural networks are usedin the control of the deployment of an occupant restraint device basedon the position of an object in a passenger compartment of a vehicle,several wave-emitting and receiving transducers are mounted on thevehicle. In one preferred embodiment, the transducers are ultrasonictransducers which simultaneously transmit and receive waves at differentfrequencies from one another. A determination is made by a first neuralnetwork whether the object is of a type requiring deployment of theoccupant restraint device in the event of a crash involving the vehiclebased on the waves received by at least some of the transducers afterbeing modified by passing through the passenger compartment. If so,another determination is made by a second neural network whether theposition of the object relative to the occupant restraint device wouldcause injury to the object upon deployment of the occupant restraintdevice based on the waves received by at least some of the transducers.The first neural network is trained on signals from at least some of thetransducers representative of waves received by the transducers whendifferent objects are situated in the passenger compartment. The secondneural network is trained on signals from at least some of thetransducers when different objects in different positions are situatedin the passenger compartment.

The transducers used in the training of the first and second neuralnetworks and operational use of method are not necessary the sametransducers and different sets of transducers can be used for the typingor categorizing of the object via the first neural network and theposition determination of the object via the second neural network.

The modifications described above with respect to the use of ultrasonictransducers can also be used in conjunction with a dual neural networksystem. For example, motion of a respective vibrating element or cone ofone or more of the transducers may be electronically or mechanicallydiminished or suppressed to reduce ringing of the transducer and/or oneor more of the transducers may be arranged in a respective tube havingan opening through which the waves are transmitted and received.

In another embodiment of the invention, a method for categorizing anddetermining the position of an object in a passenger compartment of avehicle entails mounting a plurality of wave-receiving transducers onthe vehicle, training a first neural network on signals from at leastsome of the transducers representative of waves received by thetransducers when different objects in different positions are situatedin the passenger compartment, and training a second neural network onsignals from at least some of the transducers representative of wavesreceived by the transducers when different objects in differentpositions are situated in the passenger compartment. As such, the firstneural network provides an output signal indicative of thecategorization of the object while the second neural network provides anoutput signal indicative of the position of the object. The transducersmay be controlled to transmit and receive waves each at a differentfrequency, as discussed herein, and one or more of the transducers maybe arranged in a respective tube having an opening through which thewaves are transmitted and received.

Although this system is described with particular advantageous use forultrasonic and optical transducers, it is conceivable that othertransducers other than the ultrasonics or optics can also be used inaccordance with the invention. A dual neural network is a form of amodular neural network and both are subsets of combination neuralnetworks.

The system used in a preferred implementation of at least one of theinventions disclosed herein for the determination of the presence of arear facing child seat, of an occupant or of an empty seat, for example,is the artificial neural network, which is also commonly referred to asa trained neural network. In one case, illustrated in FIG. 1, thenetwork operates on the returned signals as sensed by transducers 6, 8,9 and 10, for example. Through a training session, the system is taughtto differentiate between the different cases. This is done by conductinga large number of experiments where a selection of the possible childseats is placed in a large number of possible orientations on the frontpassenger seat. Similarly, a sufficiently large number of experimentsare run with human occupants and with boxes, bags of groceries and otherobjects (both inanimate and animate). For each experiment with differentobjects and the same object in different positions, the returned signalsfrom the transducers 6, 8, 9 and 10, for example, are associated withthe identification of the occupant in the seat or the empty seat andinformation about the occupant such as its orientation if it is a childseat and/or position. Data sets are formed from the returned signals andthe identification and information about the occupant or the absence ofan occupant. The data sets are input into a neural network-generatingprogram that creates a trained neural network that can, upon receivinginput of returned signals from the transducers 6, 8, 9 and 10, providean output of the identification and information about the occupant mostlikely situated in the seat or ascertained the existence of an emptyseat. Sometimes as many as 1,000,000 such experiments are run before theneural network is sufficiently trained and tested so that it candifferentiate among the several cases and output the correct decisionwith a very high probability. The data from each trial is combined toform a one-dimensional array of data called a vector. Of course, it mustbe realized that a neural network can also be trained to differentiateamong additional cases, for example, a forward facing child seat. It canalso be trained to recognize the existence of one or more boxes or othercargo within a truck trailer, cargo container, automobile trunk orrailroad car, for example.

Considering now FIG. 9, the normalized data from the ultrasonictransducers 6, 8, 9 and 10, the seat track position detecting sensor 74,the reclining angle detecting sensor 57, from the weight sensor(s) 7,76, from the heartbeat sensor 71, the capacitive sensor 78 and themotion sensor 73 are input to the neural network 65, and the neuralnetwork 65 is then trained on this data. More specifically, the neuralnetwork 65 adds up the normalized data from the ultrasonic transducers,from the seat track position detecting sensor 74, from the recliningangle detecting sensor 57, from the weight sensor(s) 7, 76, from theheartbeat sensor 71, from the capacitive sensor 78 and from the motionsensor 73 with each data point multiplied by an associated weightaccording to the conventional neural network process to determinecorrelation function (step S6 in FIG. 14).

Looking now at FIG. 15B, in this embodiment, 144 data points areappropriately interconnected at 25 connecting points of layer 1, andeach data point is mutually correlated through the neural networktraining and weight determination process. The 144 data points consistof 138 measured data points from the ultrasonic transducers, the data(139^(th)) from the seat track position detecting sensor 74, the data(140^(th)) from the reclining angle detecting sensor 57, the data(141^(st)) from the weight sensor(s) 7 or 76, the data (142^(nd)) fromthe heartbeat sensor 71, the data (143^(nd)) from the capacitive sensorand the data (144^(th)) from the motion sensor (the last three inputsare not shown on FIG. 15B. Each of the connecting points of the layer 1has an appropriate threshold value, and if the sum of measured dataexceeds the threshold value, each of the connecting points will output asignal to the connecting points of layer 2. Although the weight sensorinput is shown as a single input, in general there will be a separateinput from each weight sensor used. For example, if the seat has fourseat supports and a strain measuring element is used on each support,what will be four data inputs to the neural network.

The connecting points of the layer 2 comprises 20 points, and the 25connecting points of the layer 1 are appropriately interconnected as theconnecting points of the layer 2. Similarly, each data is mutuallycorrelated through the training process and weight determination. Eachof the 20 connecting points of the layer 2 has an appropriate thresholdvalue, and if the sum of measured data exceeds the threshold value, eachof the connecting points will output a signal to the connecting pointsof layer 3.

The connecting points of the layer 3 comprises 3 points, and theconnecting points of the layer 2 are interconnected at the connectingpoints of the layer 3 so that each data is mutually correlated asdescribed above. If the sum of the outputs of the connecting points oflayer 2 exceeds a threshold value, the connecting points of the latter 3will output Logic values (100), (010), and (001) respectively, forexample.

The neural network 65 recognizes the seated-state of a passenger A bytraining. Then, after training the seated-state of the passenger A anddeveloping the neural network weights, the system is tested. Thetraining procedure and the test procedure of the neural network 65 willhereafter be described with a flowchart shown in FIG. 14.

The threshold value of each connecting point is determined bymultiplying weight coefficients and summing up the results in sequence,and the aforementioned training process is to determine a weightcoefficient Wj so that the threshold value (ai) is a previouslydetermined output.ai=ΣWj·Xj(j=1 to N)

wherein

-   -   Wj is the weight coefficient,    -   Xj is the data and    -   N is the number of samples.

Based on this result of the training, the neural network 65 generatesthe weights for the coefficients of the correlation function or thealgorithm (step S7).

At the time the neural network 65 has learned a suitable number ofpatterns of the training data, the result of the training is tested bythe test data. In the case where the rate of correct answers of theseated-state detecting unit based on this test data is unsatisfactory,the neural network is further trained and the test is repeated. In thisembodiment, the test was performed based on about 600,000 test patterns.When the rate of correct test result answers was at about 98%, thetraining was ended. Further improvements to the ultrasonic occupantsensor system has now resulted in accuracies exceeding 98% and for theoptical system exceeding 99%.

The neural network software operates as follows. The training data isused to determine the weights which multiply the values at the variousnodes at the lower level when they are combined at nodes at a higherlevel. Once a sufficient number of iterations have been accomplished,the independent data is used to check the network. If the accuracy ofthe network using the independent data is lower than the last time thatit was checked using the independent data, then the previous weights aresubstituted for the new weights and training of the network continues ona different path. Thus, although the independent data is not used totrain the network, it does strongly affect the weights. It is thereforenot really independent. Also, both the training data and the independentdata are created so that all occupancy states are roughly equallyrepresented. As a result, a third set of data is used which isstructured to more closely represent the real world of vehicleoccupancy. This third data set, the “real world” data, is then used toarrive at a figure as to the real accuracy of the system.

The neural network 65 has outputs 65 a, 65 b and 65 c (FIG. 9). Each ofthe outputs 65 a, 65 b and 65 c outputs a signal of logic 0 or 1 to agate circuit or algorithm 77. Based on the signals from the outputs 65a, 65 b and 65 c, any one of these combination (100), (010) and (001) isobtained. In another preferred embodiment, all data for the empty seatwas removed from the training set and the empty seat case was determinedbased on the output of the weight sensor alone. This simplifies theneural network and improves its accuracy.

In this embodiment, the output (001) correspond to a vacant seat, a seatoccupied by an inanimate object or a seat occupied by a pet (VACANT),the output (010) corresponds to a rear facing child seat (RFCS) or anabnormally seated passenger (ASP or OOPA), and the output (100)corresponds to a normally seated passenger (NSP or FFA) or a forwardfacing child seat (FFCS).

The gate circuit (seated-state evaluation circuit) 77 can be implementedby an electronic circuit or by a computer algorithm by those skilled inthe art and the details will not be presented here. The function of thegate circuit 77 is to remove the ambiguity that sometimes results whenultrasonic sensors and seat position sensors alone are used. Thisambiguity is that it is sometimes difficult to differentiate between arear facing child seat (RFCS) and an abnormally seated passenger (ASP),or between a normally seated passenger (NSP) and a forward facing childseat (FFCS). By the addition of one or more weight sensors in thefunction of acting as a switch when the weight is above or below 60lbs., it has been found that this ambiguity can be eliminated. The gatecircuit therefore takes into account the output of the neural networkand also the weight from the weight sensor(s) as being above or below 60lbs. and thereby separates the two cases just described and results infive discrete outputs.

The use of weight data must be heavily filtered since during drivingconditions, especially on rough roads or during an accident, the weightsensors will give highly varying output. The weight sensors, therefore,are of little value during the period of time leading up to andincluding a crash and their influence must be minimized during this timeperiod. One way of doing this is to average the data over a long periodof time such as from 5 seconds to a minute or more.

Thus, the gate circuit 77 fulfills a role of outputting five kinds ofseated-state evaluation signals, based on a combination of three kindsof evaluation signals from the neural network 65 and superimposedinformation from the weight sensor(s). The five seated-state evaluationsignals are input to an airbag deployment determining circuit that ispart of the airbag system and will not be described here. Output of thissystem can also be used to activate a variety of lights or alarms toindicate to the operator of the vehicle the seated state of thepassenger. The system that has been described here for the passengerside is also applicable for the most part for the driver side.

An alternate and preferred method of accomplishing the functionperformed by the gate circuit is to use a modular neural network. Inthis case, the first level neural network is trained on determiningwhether the seat is occupied or vacant. The input to this neural networkconsists of all of the data points described above. Since the onlyfunction of this neural network is to ascertain occupancy, the accuracyof this neural network is very high. If this neural network determinesthat the seat is not vacant, then the second level neural networkdetermines the occupancy state of the seat.

In this embodiment, although the neural network 65 has been employed asan evaluation circuit, the mapping data of the coefficients of acorrelation function may also be implemented or transferred to amicrocomputer to constitute the evaluation circuit (see Step S8 in FIG.14).

According to the seated-state detecting unit of the present invention,the identification of a vacant seat (VACANT), a rear facing child seat(RFCS), a forward facing child seat (FFCS), a normally seated adultpassenger (NSP), an abnormally seated adult passenger (ASP), can bereliably performed. Based on this identification, it is possible tocontrol a component, system or subsystem in the vehicle. For example, aregulation valve which controls the inflation or deflation of an airbagmay be controlled based on the evaluated identification of the occupantof the seat. This regulation valve may be of the digital or analog type.A digital regulation valve is one that is in either of two states, openor closed. The control of the flow is then accomplished by varying thetime that the valve is open and closed, i.e., the duty cycle.

The neural network has been previously trained on a significant numberof occupants of the passenger compartment. The number of such occupantsdepends strongly on whether the driver or the passenger seat is beinganalyzed. The variety of seating states or occupancies of the passengerseat is vastly greater than that of the driver seat. For the driverseat, a typical training set will consist of approximately 100 differentvehicle occupancies. For the passenger seat, this number can exceed1000. These numbers are used for illustration purposes only and willdiffer significantly from vehicle model to vehicle model. Of course manyvectors of data will be taken for each occupancy as the occupant assumesdifferent positions and postures.

The neural network is now used to determine which of the storedoccupancies most closely corresponds to the measured data. The output ofthe neural network can be an index of the setup that was used duringtraining that most closely matches the current measured state. Thisindex can be used to locate stored information from the matched trainedoccupancy. Information that has been stored for the trained occupancytypically includes the locus of the centers of the chest and head of thedriver, as well as the approximate radius of pixels which is associatedwith this center to define the head area, for example. For the case ofFIG. 8A, it is now known from this exercise where the head, chest, andperhaps the eyes and ears, of the driver are most likely to be locatedand also which pixels should be tracked in order to know the preciseposition of the driver's head and chest. What has been described aboveis the identification process for automobile occupancy and is onlyrepresentative of the general process. A similar procedure, althoughusually simpler with fewer steps, is applicable to other vehiclemonitoring cases.

The use of trainable pattern recognition technologies such as neuralnetworks is an important part of the some of the inventions disclosesherein particularly for the automobile occupancy case, although othernon-trained pattern recognition systems such as fuzzy logic,correlation, Kalman filters, and sensor fusion can also be used. Thesetechnologies are implemented using computer programs to analyze thepatterns of examples to determine the differences between differentcategories of objects. These computer programs are derived using a setof representative data collected during the training phase, called thetraining set. After training, the computer programs output a computeralgorithm containing the rules permitting classification of the objectsof interest based on the data obtained after installation in thevehicle. These rules, in the form of an algorithm, are implemented inthe system that is mounted onto the vehicle. The determination of theserules is important to the pattern recognition techniques used in atleast one of the inventions disclosed herein. Artificial neural networksusing back propagation are thus far the most successful of the ruledetermination approaches, however, research is underway to developsystems with many of the advantages of back propagation neural networks,such as learning by training, without the disadvantages, such as theinability to understand the network and the possibility of notconverging to the best solution. In particular, back propagation neuralnetworks will frequently give an unreasonable response when presentedwith data than is not within the training data. It is well known thatneural networks are good at interpolation but poor at extrapolation. Acombined neural network fuzzy logic system, on the other hand, cansubstantially solve this problem. Additionally, there are many otherneural network systems in addition to back propagation. In fact, onetype of neural network may be optimum for identifying the contents ofthe passenger compartment and another for determining the location ofthe object dynamically.

Numerous books and articles, including more than 500 U.S. patents,describe neural networks in great detail and thus the theory andapplication of this technology is well known and will not be repeatedhere. Except in a few isolated situations where neural networks had beenused to solve particular problems limited to engine control, forexample, they had not previously been applied to automobiles, trucks orother vehicle monitoring situations.

The system generally used in the instant invention, therefore, for thedetermination of the presence of a rear facing child seat, an occupant,or an empty seat is the artificial neural network or a neural-fuzzysystem. In this case, the network operates on the returned signals froma CCD or CMOS array as sensed by transducers 49, 50, 51 and 54 in FIG.8D, for example. For the case of the front passenger seat, for example,through a training session, the system is taught to differentiatebetween the three cases. This is done by conducting a large number ofexperiments where available child seats are placed in numerous positionsand orientations on the front passenger seat of the vehicle.

Once the network is determined, it is possible to examine the result todetermine, from the algorithm created by the neural network software,the rules that were finally arrived at by the trial and error trainingtechnique. In that case, the rules can then be programmed into amicroprocessor. Alternately, a neural computer can be used to implementthe neural network directly. In either case, the implementation can becarried out by those skilled in the art of pattern recognition usingneural networks. If a microprocessor is used, a memory device is alsorequired to store the data from the analog to digital converters whichdigitize the data from the receiving transducers. On the other hand, ifa neural network computer is used, the analog signal can be fed directlyfrom the transducers to the neural network input nodes and anintermediate memory is not required. Memory of some type is needed tostore the computer programs in the case of the microprocessor system andif the neural computer is used for more than one task, a memory isneeded to store the network specific values associated with each task.

A review of the literature on neural networks yields the conclusion thatthe use of such a large training set is unique in the neural networkfield. The rule of thumb for neural networks is that there must be atleast three training cases for each network weight. Thus, for example,if a neural network has 156 input nodes, 10 first hidden layer nodes, 5second hidden layer nodes, and one output node this results in a totalof 1,622 weights. According to conventional theory 5000 trainingexamples should be sufficient. It is highly unexpected, therefore, thatgreater accuracy would be achieved through 100 times that many cases. Itis thus not obvious and cannot be deduced from the neural networkliterature that the accuracy of the system will improve substantially asthe size of the training database increases even to tens of thousands ofcases. It is also not obvious looking at the plots of the vectorsobtained using ultrasonic transducers that increasing the number oftests or the database size will have such a significant effect on thesystem accuracy. Each of the vectors is typically a rather course plotwith a few significant peaks and valleys. Since the spatial resolutionof an ultrasonic system is typically about 2 to 4 inches, it is onceagain surprising that such a large database is required to achievesignificant accuracy improvements.

The back propagation neural network is a very successful general-purposenetwork. However, for some applications, there are other neural networkarchitectures that can perform better. If it has been found, forexample, that a parallel network as described above results in asignificant improvement in the system, then, it is likely that theparticular neural network architecture chosen has not been successful inretrieving all of the information that is present in the data. In such acase, an RCE, Stochastic, Logicon Projection, cellular, support vectormachine or one of the other approximately 30 types of neural networkarchitectures can be tried to see if the results improve. This parallelnetwork test, therefore, is a valuable tool for determining the degreeto which the current neural network is capable of using efficiently theavailable data.

One of the salient features of neural networks is their ability of findpatterns in data regardless of its source. Neural networks work wellwith data from ultrasonic sensors, optical imagers, strain gage andbladder weight sensors, temperature sensors, chemical sensors, radiationsensors, pressure sensors, electric field sensors, capacitance basedsensors, any other wave sensors including the entire electromagneticspectrum, etc. If data from any sensors can be digitized and fed into aneural network generating program and if there is information in thepattern of the data then neural networks can be a viable method ofidentifying those patterns and correlating them with a desired outputfunction. Note that although the inventions disclosed herein preferablyuse neural networks and combination neural networks to be describednext, these inventions are not limited to this form or method of patternrecognition. The major breakthrough in occupant sensing came with therecognition by the current assignee that ordinary analysis usingmathematical equations where the researcher looks at the data andattempts, based on the principles of statistics, engineering or physics,to derive the relevant relationships between the data and the categoryand location of an occupying item, is not the proper approach and thatpattern recognition technologies should be used. This is believed to bethe first use of such pattern recognition technologies in the automobilesafety and monitoring fields with the exception that neural networkshave been used by the current assignee and others as the basis of acrash sensor algorithm and by certain automobile manufacturers forengine control. Note for many monitoring situations in truck trailers,cargo containers and railroad cars where questions such as “is thereanything in the vehicle?” are asked, neural networks may not always berequired.

11.2 Combination Neural Networks

The technique described above for the determination of the location ofan occupant during panic or braking pre-crash situations involves use ofa modular neural network. In that case, one neural network was used todetermine the occupancy state of the vehicle and one or more neuralnetworks were used to determine the location of the occupant within thevehicle. The method of designing a system utilizing multiple neuralnetworks is a key teaching of the present invention. When this idea isgeneralized, many potential combinations of multiple neural networkarchitectures become possible. Details about this are found in the '996application, section 11.2, incorporated by reference herein.

11.3 Interpretation of Other Occupant States

Once a vehicle interior monitoring system employing a sophisticatedpattern recognition system, such as a neural network or modular neuralnetwork, is in place, it is possible to monitor the motions of thedriver over time and determine if he is falling asleep or has otherwisebecome incapacitated. In such an event, the vehicle can be caused torespond in a number of different ways. One such system is illustrated inFIG. 6 and consists of a monitoring system having transducers 8 and 9plus microprocessor 20 programmed to compare the motions of the driverover time and trained to recognize changes in behavior representative ofbecoming incapacitated e.g., the eyes blinking erratically and remainingclosed for ever longer periods of time. If the system determines thatthere is a reasonable probability that the driver has fallen asleep, forexample, then it can turn on a warning light shown here as 41 or send awarning sound. If the driver fails to respond to the warning by pushinga button 43, for example, then the horn and lights can be operated in amanner to warn other vehicles and the vehicle brought to a stop. Onenovel approach, not shown, would be to use the horn as the button 43.For a momentary depression of the horn, for this case, the horn wouldnot sound. Other responses can also be programmed and other tests ofdriver attentiveness can be used, without resorting to attempting tomonitor the motions of the driver's eyes that would signify that thedriver was alert. These other responses can include an input to thesteering wheel, motion of the head, blinking or other motion of the eyesetc. In fact, by testing a large representative sample of the populationof drivers, the range of alert responses to the warning light and/orsound can be compared to the lack of response of a sleeping driver andthereby the state of attentiveness determined.

An even more sophisticated system of monitoring the behavior of thedriver is to track his eye motions using such techniques as aredescribed in U.S. Pat. Nos. 4,648,052, 4,720,189, 4,836,670, 4,950,069,5,008,946 and 5,305,012. Detection of the impaired driver in particularcan be best determined by these techniques. These systems use patternrecognition techniques plus, in many cases, the transmitter and CCDreceivers must be appropriately located so that the reflection off ofthe cornea of the driver's eyes can be detected as discussed inabove-referenced patents. The size of the CCD arrays used herein permitstheir location, sometimes in conjunction with a reflective windshield,where this corneal reflection can be detected with some difficulty.Sunglasses or other items can interfere with this process.

In a similar manner as described in these patents, the motion of thedriver's eyes can be used to control various systems in the vehiclepermitting hands off control of the entertainment system, heating andair conditioning system or all of the other systems described above.Although some of these systems have been described in theafore-mentioned patents, none have made use of neural networks forinterpreting the eye movements. The use of particular IR wavelengthspermits the monitoring of the driver's eyes without the driver knowingthat this is occurring. IR with a wave length above about 1.1 microns,however, is blocked by glass eyeglasses and thus other invisiblefrequencies may be required.

The use of the windshield as a reflector is particularly useful whenmonitoring the eyes of the driver by means of a camera mounted on therear view mirror assembly. The reflections from the cornea are highlydirectional, as every driver knows whose lights have reflected off theeyes of an animal on the roadway. For this to be effective, the eyes ofthe driver must be looking at the radiation source. Since the driver ispresumably looking through the windshield, the source of the radiationmust also come from the windshield and the reflections from the driver'seyes must also be in the direction of the windshield. Using thistechnique, the time that the driver spends looking through thewindshield can be monitored and if that time drops below some thresholdvalue, it can be presumed that the driver is not attentive and may besleeping or otherwise incapacitated.

The location of the eyes of the driver, for this application, is greatlyfacilitated by the teachings of the inventions as described above.Although others have suggested the use of eye motions and cornealreflections for drowsiness determination, up until now there has notbeen a practical method for locating the driver's eyes with sufficientprecision and reliability as to render this technique practical. Also,although sunglasses might defeat such a system, most drowsiness causedaccidents happen at night when it is less likely that sunglasses areworn.

11.4 Other Aspects

Various modifications to pattern recognition techniques are described insections 11.4, 11.5, 11.6. 11.7 and 11.8 of the '996 application,including for example pre-processing of data prior to analysis to deriveinformation from the data, post-processing of output from a patternrecognition system to improve the value of the output and use of asingle imager optical occupant classification system.

12. Optical Correlators

A discussion of optical correlation systems, i.e., fast optical patternrecognition systems, which may be applied in the invention is set forthin the '996 application, section 12.

13. Other Products, Outputs, Features

Once the occupancy state of the seat (or seats) in the vehicle or of thevehicle itself, as in a cargo container, truck trailer or railroad car,is known, this information can be used to control or affect theoperation of a significant number of vehicular systems, components anddevices. That is, the systems, components and devices in the vehicle canbe controlled and perhaps their operation optimized in consideration ofthe occupancy of the seat(s) in the vehicle or of the vehicle itself.Thus, the vehicle includes a control system coupled to the processor forcontrolling a component or device in the vehicle in consideration of theoutput indicative of the current occupancy state of the seat obtainedfrom the processor. The component or device can be an airbag systemincluding at least one deployable airbag whereby the deployment of theairbag is suppressed, for example, if the seat is occupied by arear-facing child seat, or otherwise the parameters of the deploymentare controlled. Thus, the seated-state detecting unit described abovemay be used in a component adjustment system and method described belowwhen the presence of a human being occupying the seat is detected. Thecomponent can also be a telematics system such as the Skybitz or OnStarsystems where information about the occupancy state of the vehicle, orchanges in that state, can be sent to a remote site.

The component adjustment system and methods in accordance with theinvention can automatically and passively adjust the component based onthe morphology of the occupant of the seat. As noted above, theadjustment system may include the seated-state detecting unit describedabove so that it will be activated if the seated-state detecting unitdetects that an adult or child occupant is seated on the seat, that is,the adjustment system will not operate if the seat is occupied by achild seat, pet or inanimate objects. Obviously, the same system can beused for any seat in the vehicle including the driver seat and thepassenger seat(s). This adjustment system may incorporate the samecomponents as the seated-state detecting unit described above, that is,the same components may constitute a part of both the seated-statedetecting unit and the adjustment system, for example, the weightmeasuring system.

The adjustment system described herein, although improved over the priorart, will at best be approximate since two people, even if they areidentical in all other respects, may have a different preferred drivingposition or other preferred adjusted component location or orientation.A system that automatically adjusts the component, therefore, shouldlearn from its errors. Thus, when a new occupant sits in the vehicle,for example, the system automatically estimates the best location of thecomponent for that occupant and moves the component to that location,assuming it is not already at the best location. If the occupant changesthe location, the system should remember that change and incorporate itinto the adjustment the next time that person enters the vehicle and isseated in the same seat. Therefore, the system need not make a perfectselection the first time but it should remember the person and theposition the component was in for that person. The system, therefore,makes one, two or three measurements of morphological characteristics ofthe occupant and then adjusts the component based on an algorithm. Theoccupant will correct the adjustment and the next time that the systemmeasures the same measurements for those measurement characteristics, itwill set the component to the corrected position. As such, preferredcomponents for which the system in accordance with the invention is mostuseful are those which affect a driver of the vehicle and relate to thesensory abilities of the driver, i.e., the mirrors, the seat, thesteering wheel and steering column and accelerator, clutch and brakepedals.

Thus, although the above description mentions that the airbag system canbe controlled by the control circuitry 20 (FIG. 1), any vehicularsystem, component or subsystem can be controlled based on theinformation or data obtained by transmitter and/or receiver assemblies6, 8, 9 and 10. Control circuitry 20 can be programmed or trained, iffor example a neural network is used, to control heating anair-conditioning systems based on the presence of occupants in certainpositions so as to optimize the climate control in the vehicle. Theentertainment system can also be controlled to provide sound only tolocations at which occupants are situated. There is no limit to thenumber and type of vehicular systems, components and subsystems that canbe controlled using the analysis techniques described herein.

Furthermore, if multiple vehicular systems are to be controlled bycontrol circuitry 20, then these systems can be controlled by thecontrol circuitry 20 based on the status of particular components of thevehicle. For example, an indication of whether a key is in the ignitioncan be used to direct the control circuitry 20 to either control anairbag system (when the key is present in the ignition) or an antitheftsystem (when the key is not present in the ignition). Control circuitry20 would thus be responsive to the status of the ignition of the motorvehicle to perform one of a plurality of different functions. Moreparticularly, the pattern recognition algorithm, such as the neuralnetwork described herein, could itself be designed to perform in adifferent way depending on the status of a vehicular component such asthe detected presence of a key in the ignition. It could provide oneoutput to control an antitheft system when a key is not present andanother output when a key is present using the same inputs from thetransmitter and/or receiver assemblies 6, 8, 9 and 10. In oneembodiment, a neural network, when used as the pattern recognitionalgorithm, can perform different functions as a function of the statusof the ignition. If the neural network is a combination or modularneural network, the neural network being provided with input data maydepend on the status of the ignition.

The algorithm in control circuitry 20 can also be designed to determinethe location of the occupant's eyes either directly or indirectlythrough a determination of the location of the occupant and anestimation of the position of the eyes therefrom. As such, the positionof the rear view mirror 55 can be adjusted to optimize the driver's usethereof.

Once a characteristic of the object is obtained, it can be used fornumerous purposes. For example, the processor can be programmed tocontrol a reactive component, system or subsystem 103 in FIG. 20 basedon the determined characteristic of the object. When the reactivecomponent is an airbag assembly including one or more airbags, theprocessor can control one or more deployment parameters of theairbag(s).

The apparatus can operate in a manner as illustrated in FIG. 30 whereinas a first step 335, one or more images of the environment are obtained.One or more characteristics of objects in the images are determined at336, using, for example, pattern recognition techniques, and then one ormore components are controlled at 337 based on the determinedcharacteristics. The process of obtaining and processing the images, orthe processing of data derived from the images or data representative ofthe images, is periodically continued at least throughout the operationof the vehicle.

13.1 Control of Passive Restraints

Use of the vehicle interior monitoring system to control the deploymentof an airbag is discussed in U.S. Pat. No. 5,653,462. In that case, thecontrol is based on the use of a pattern recognition system, such as aneural network, to differentiate between the occupant and hisextremities in order to provide an accurate determination of theposition of the occupant relative to the airbag. If the occupant issufficiently close to the airbag module that he is more likely to beinjured by the deployment itself than by the accident, the deployment ofthe airbag is suppressed. This process is carried further by theinterior monitoring system described herein in that the nature oridentity of the object occupying the vehicle seat is used to contributeto the airbag deployment decision. FIG. 4 shows a side view illustratingschematically the interface between the vehicle interior monitoringsystem of at least one of the inventions disclosed herein and thevehicle airbag system 44. A similar system can be provided for thepassenger as described in U.S. Pat. No. 6,820,897.

In this embodiment, ultrasonic transducers 8 and 9 transmit bursts ofultrasonic waves that travel to the occupant where they are reflectedback to transducers or receptors/receivers 8 and 9. The time periodrequired for the waves to travel from the generator and return is usedto determine the distance from the occupant to the airbag as describedin U.S. Pat. No. 5,653,462, i.e., and thus may also be used to determinethe position or location of the occupant. An optical imager based systemwould also be appropriate. In the invention, however, the portion of thereturn signal that represents the occupants' head or chest, has beendetermined based on pattern recognition techniques such as a neuralnetwork. The relative velocity of the occupant toward the airbag canthen be determined, by Doppler principles or from successive positionmeasurements, which permits a sufficiently accurate prediction of thetime when the occupant would become proximate to the airbag. Bycomparing the occupant relative velocity to the integral of the crashdeceleration pulse, a determination as to whether the occupant is beingrestrained by a seatbelt can also be made which then can affect theairbag deployment initiation decision. Alternately, the mere knowledgethat the occupant has moved a distance that would not be possible if hewere wearing a seatbelt gives information that he is not wearing one.

Another method of providing a significant improvement to the problem ofdetermining the position of the occupant during vehicle deceleration isto input the vehicle deceleration directly into the occupant sensingsystem. This can be done through the use of the airbag crash sensoraccelerometer or a dedicated accelerometer can be used. Thisdeceleration or its integral can be entered directly into the neuralnetwork or can be integrated through an additional post-processingalgorithm. Post processing in general is discussed in section 11.7. Onesignificant advantage of neural networks is their ability to efficientlyuse information from any source. It is the ultimate “sensor fusion”system.

A more detailed discussion of this process and of the advantages of thevarious technologies, such as acoustic or electromagnetic, can be foundin SAE paper 940527, “Vehicle Occupant Position Sensing” by Breed etal., In this paper, it is demonstrated that the time delay required foracoustic waves to travel to the occupant and return does not prevent theuse of acoustics for position measurement of occupants during the crashevent. For position measurement and for many pattern recognitionapplications, ultrasonics is the preferred technology due to the lack ofadverse health effects and the low cost of ultrasonic systems comparedwith either camera, laser or radar based systems. This situation haschanged, however, as the cost of imagers has come down. The mainlimiting feature of ultrasonics is the wavelength, which places alimitation on the size of features that can be discerned. Opticalsystems, for example, are required when the identification of particularindividuals is desired.

FIG. 31 is a schematic drawing of one embodiment of an occupantrestraint device control system in accordance with the invention. Thefirst step is to obtain information about the contents of the seat atstep 338, when such contents are present on the seat. To this end, apresence sensor can be employed to activate the system only when thepresence of an object, or living being, is detected. Next, at step 339,a signal is generated based on the contents of the seat, with differentsignals being generated for different contents of the seat. Thus, whilea signal for a dog will be different than the signal for a child set,the signals for different child seats will not be that different. Next,at step 340, the signal is analyzed to determine whether a child seat ispresent, whether a child seat in a particular orientation is presentand/or whether a child seat in a particular position is present.Deployment control 341 provides a deployment control signal or commandbased on the analysis of the signal generated based on the contents ofthe seat. This signal or command is directed to the occupant protectionor restraint device 342 to provide for deployment for that particularcontent of the seat. The system continually obtains information aboutthe contents of the seat until such time as a deployment signal isreceived from, e.g., a crash sensor, to initiate deployment of theoccupant restraint device.

FIG. 32 is a flow chart of the operation of one embodiment of anoccupant restraint device control method in accordance with theinvention. The first step is to determine whether contents are presenton the seat at step 910. If so, information is obtained about thecontents of the seat at step 344. At step 345, a signal is generatedbased on the contents of the seat, with different signals beinggenerated for different contents of the seat. The signal is analyzed todetermine whether a child seat is present at step 346, whether a childseat in a particular orientation is present at step 347 and/or whether achild seat in a particular position is present at step 348. Deploymentcontrol 349 provides a deployment control signal or command based on theanalysis of the signal generated based on the contents of the seat. Thissignal or command is directed to the occupant protection or restraintdevice 350 to provide for deployment for those particular contents ofthe seat. The system continually obtains information about the contentsof the seat until such time as a deployment signal is received from,e.g., a crash sensor 351, to initiate deployment of the occupantrestraint device.

In another implementation, the sensor algorithm may determine the ratethat gas is generated to affect the rate that the airbag is inflated. Inall of these cases, the position of the occupant is used to affect thedeployment of the airbag either as to whether or not it should bedeployed at all, the time of deployment and/or the rate of inflationand/or deflation.

Such a system can also be used to positively identify or confirm thepresence of a rear facing child seat in the vehicle, if the child seatis equipped with a resonator. In this case, a resonator 18 is placed onthe forward most portion of the child seat, or in some other convenientposition, as shown in FIG. 1. The resonator 18, or other type of signalgenerating device, such as an RFID tag, which generates a signal uponexcitation, e.g., by a transmitted energy signal, can be used not onlyto determine the orientation of the child seat but also to determine theposition of the child seat (in essentially the same manner as describedabove with respect to determining the position of the seat and theposition of the seatbelt).

The determination of the presence of a child seat can be used to affectanother system in the vehicle. Most importantly, deployment of anoccupant restraint device can be controlled depending on whether a childseat is present. Control of the occupant restraint device may entailsuppression of deployment of the device. If the occupant restraintdevice is an airbag, e.g., a frontal airbag or a side airbag, control ofthe airbag deployment may entail not only suppression of the deploymentbut also depowered deployment, adjustment of the orientation of theairbag, adjustment of the inflation rate or inflation time and/oradjustment of the deflation rate or time.

Several systems are in development for determining the location of anoccupant and modifying the deployment of the airbag based of his or herposition. These systems are called “smart airbags”. The passive seatcontrol system in accordance with at least one of the inventionsdisclosed herein can also be used for this purpose as illustrated inFIG. 33. This figure shows an inflated airbag 352 and an arrangement forcontrolling both the flow of gas into and out of the airbag during acrash. The determination is made based on height sensors 353, 354 and355 (FIG. 29) located in the headrest, a weight sensor 252 in the seatand the location of the seat which is known by control circuit 254.Other smart airbags systems rely only on the position of the occupantdetermined from various position sensors using ultrasonics or opticalsensors, or equivalent.

The weight sensor coupled with the height sensor and the occupant'svelocity relative to the vehicle, as determined by the occupant positionsensors, provides information as to the amount of energy that the airbagwill need to absorb during the impact of the occupant with the airbag.This, along with the location of the occupant relative to the airbag, isthen used to determine the amount of gas that is to be injected into theairbag during deployment and the size of the exit orifices that controlthe rate of energy dissipation as the occupant is interacting with theairbag during the crash. For example, if an occupant is particularlyheavy then it is desirable to increase the amount of gas, and thus theinitial pressure, in the airbag to accommodate the larger force whichwill be required to arrest the relative motion of the occupant. Also,the size of the exit orifices should be reduced, since there will be alarger pressure tending to force the gas out of the orifices, in orderto prevent the bag from bottoming out before the occupant's relativevelocity is arrested. Similarly, for a small occupant the initialpressure would be reduced and the size of the exit orifices increased.If, on the other hand, the occupant is already close to the airbag thenthe amount of gas injected into the airbag will need to be reduced.

Another and preferred approach is to incorporate an accelerometer intothe seatbelt or the airbag surface and to measure the deceleration ofthe occupant and to control the outflow of gas from the airbag tomaintain the occupant's chest acceleration below some maximum value suchas 40 Gs. This maximum value can be set based on the forecasted severityof the crash. If the occupant is wearing a seatbelt the outflow from theairbag can be significantly reduced since the seatbelt is taking up mostof the load and the airbag then should be used to help spread the loadover more of the occupant's chest. Although the pressure in the airbagis one indication of the deceleration being imparted to the occupant itis a relatively crude measure since it does not take into account themass of the occupant. Since it is acceleration that should be controlledit is better to measure acceleration rather than pressure in the airbag.

There are many ways of varying the amount of gas injected into theairbag some of which are covered in the patent literature and include,for example, inflators where the amount of gas generated and the rate ofgeneration is controllable. For example, in a particular hybrid inflatoronce manufactured by the Allied Signal Corporation, two pyrotechniccharges are available to heat the stored gas in the inflator. Either orboth of the pyrotechnic charges can be ignited and the timing betweenthe ignitions can be controlled to significantly vary the rate of gasflow to the airbag.

The flow of gas out of the airbag is traditionally done through fixeddiameter orifices placed in the bag fabric. Some attempts have been madeto provide a measure of control through such measures as blowout patchesapplied to the exterior of the airbag. Other systems were disclosed inU.S. patent application Ser. No. 07/541,464 filed Feb. 9, 1989, nowabandoned.

FIG. 33A illustrates schematically an inflator 357 generating gas tofill airbag 352 through control valve 358. If the control valve 358 isclosed while a pyrotechnic generator is operating, provision must bemade to store or dump the gas being generated so to prevent the inflatorfrom failing from excess pressure. The flow of gas out of airbag 352 iscontrolled by exit control valve 359. The exit valve 359 can beimplemented in many different ways including, for example, a motoroperated valve located adjacent the inflator and in fluid communicationwith the airbag or a digital flow control valve as discussed herein.When control circuit 254 (FIG. 29) determines the size and weight of theoccupant, the seat position and the relative velocity of the occupant,it then determines the appropriate opening for the exit valve 359, whichis coupled to the control circuit 254. A signal is then sent fromcontrol circuit 254 to the motor controlling this valve which providesthe proper opening.

Consider, for example, the case of a vehicle that impacts with a pole orbrush in front of a barrier. The crash sensor system may deduce thatthis is a low velocity crash and only initiate the first inflatorcharge. Then as the occupant is moving close to the airbag the barrieris struck but it may now be too late to get the benefit of the secondcharge. For this case, a better solution might be to always generate themaximum amount of gas but to store the excess in a supplemental chamberuntil it is needed.

In a like manner, other parameters can also be adjusted, such as thedirection of the airbag, by properly positioning the angle and locationof the steering wheel relative to the driver. If seatbelt pretensionersare used, the amount of tension in the seatbelt or the force at whichthe seatbelt spools out, for the case of force limiters, could also beadjusted based on the occupant morphological characteristics determinedby the system of at least one of the inventions disclosed herein. Theforce measured on the seatbelt, if the vehicle deceleration is known,gives a confirmation of the mass of the occupant. This force measurementcan also be used to control the chest acceleration given to the occupantto minimize injuries caused by the seatbelt. As discussed above, it isbetter to measure the acceleration of the chest directly.

In the embodiment shown in FIG. 8A, transmitter/receiver assemblies 49,50, 51 and 54 emit infrared waves that reflect off of the head and chestof the driver and return thereto. Periodically, the device, as commandedby control circuitry 20, transmits a pulse of infrared waves and thereflected signal is detected by the same (i.e. the LEDs and imager arein the same housing) or a different device. The transmitters can eithertransmit simultaneously or sequentially. An associated electroniccircuit and algorithm in control circuitry 20 processes the returnedsignals as discussed above and determines the location of the occupantin the passenger compartment. This information is then sent to the crashsensor and diagnostic circuitry, which may also be resident in controlcircuitry 20 (programmed within a control module), which determines ifthe occupant is close enough to the airbag that a deployment might, byitself, cause injury which exceeds that which might be caused by theaccident itself. In such a case, the circuit disables the airbag systemand thereby prevents its deployment.

In an alternate case, the sensor algorithm assesses the probability thata crash requiring an airbag is in process and waits until thatprobability exceeds an amount that is dependent on the position of theoccupant. Thus, for example, the sensor might decide to deploy theairbag based on a need probability assessment of 50%, if the decisionmust be made immediately for an occupant approaching the airbag, butmight wait until the probability rises above 95% for a more distantoccupant. In the alternative, the crash sensor and diagnostic circuitryoptionally resident in control circuitry 20 may tailor the parameters ofthe deployment (time to initiation of deployment, rate of inflation,rate of deflation, deployment time, etc.) based on the current positionand possibly velocity of the occupant, for example a depowereddeployment.

In another implementation, the sensor algorithm may determine the ratethat gas is generated to affect the rate that the airbag is inflated.One method of controlling the gas generation rate is to control thepressure in the inflator combustion chamber. The higher the internalpressure the faster gas is generated. Once a method of controlling thegas combustion pressure is implemented, the capability exists tosignificantly reduce the variation in inflator properties withtemperature. At lower temperatures the pressure control system wouldincrease the pressure in the combustion chamber and at higher ambienttemperatures it would reduce the pressure. In all of these cases, theposition of the occupant can be used to affect the deployment of theairbag as to whether or not it should be deployed at all, the time ofdeployment and/or the rate of inflation.

The applications described herein have been illustrated using the driverand sometimes the passenger of the vehicle. The same systems ofdetermining the position of the occupant relative to the airbag apply toa driver, front and rear seated passengers, sometimes requiring minormodifications. It is likely that the sensor required triggering timebased on the position of the occupant will be different for the driverthan for the passenger. Current systems are based primarily on thedriver with the result that the probability of injury to the passengeris necessarily increased either by deploying the airbag too late or byfailing to deploy the airbag when the position of the driver would notwarrant it but the passenger's position would. With the use of occupantposition sensors for the passenger and driver, the airbag system can beindividually optimized for each occupant and result in furthersignificant injury reduction. In particular, either the driver orpassenger system can be disabled if either the driver or passenger isout-of-position or if the passenger seat is unoccupied.

There is almost always a driver present in vehicles that are involved inaccidents where an airbag is needed. Only about 30% of these vehicles,however, have a passenger. If the passenger is not present, there isusually no need to deploy the passenger side airbag. The occupantmonitoring system, when used for the passenger side with proper patternrecognition circuitry, can also ascertain whether or not the seat isoccupied, and if not, can disable the deployment of the passenger sideairbag and thereby save the cost of its replacement. The same strategyapplies also for monitoring the rear seat of the vehicle. Also, atrainable pattern recognition system, as used herein, can distinguishbetween an occupant and a bag of groceries, for example. Finally, therehas been much written about the out-of-position child who is standing orotherwise positioned adjacent to the airbag, perhaps due to pre-crashbraking. The occupant position sensor described herein can prevent thedeployment of the airbag in this situation as well as in the situationof a rear facing child seat as described above.

As discussed herein, occupant sensors can also be used for monitoringthe rear seats of the vehicle for the purpose, among others, ofcontrolling airbag or other restraint deployment.

13.2 Seat, Seatbelt, Steering Wheel and Pedal Adjustment and Resonators

Acoustic or electromagnetic resonators are active or passive devicesthat resonate at a preset frequency when excited at that frequency.Since this device can be identified, it provides a particularlyeffective method of determining the distance to a particular point inthe vehicle passenger compartment (i.e., the distance between thelocation of the resonator and the detector), and thus the position of anobject or component equipped with a device. Additional details about theuse of resonators and reflectors are found in the '996 application,section 13.2.

Let us now consider the adjustment of a seat to adapt to an occupant.First some measurements of the morphological properties of the occupantare necessary. The first characteristic considered is a measurement ofthe height of the occupant from the vehicle seat. This can be done by asensor in the ceiling of the vehicle but this becomes difficult since,even for the same seat location, the head of the occupant will not be atthe same angle with respect to the seat and therefore the angle to aceiling mounted sensor is in general unknown at least as long as onlyone ceiling mounted sensor is used. This problem can be solved if two orthree sensors are used as described below. The simplest implementationis to place the sensor in the seat. In U.S. Pat. No. 5,694,320, a rearimpact occupant protection apparatus is disclosed which uses sensorsmounted within the headrest. This same system can also be used tomeasure the height of the occupant from the seat and thus, for noadditional cost assuming the rear impact occupant protection systemdescribed in the '320 patent is provided, the first measure of theoccupant's morphology can be achieved. For some applications, this maybe sufficient since it is unlikely that two operators will use thevehicle that both have the same height. For other implementations, oneor more additional measurements are used. A face, fingerprint,voiceprint or iris recognition system will have the least problemidentifying a previous occupant.

Referring now to FIG. 28, an automatic adjustment system for adjusting aseat (which is being used only as an example of a vehicle component) isshown generally at 371 with a movable headrest 356 and ultrasonicsensors 353, 354 and 355 for measuring the height of the occupant of theseat. Other types of wave, energy or radiation receiving sensors mayalso be used in the invention instead of the ultrasonictransmitter/receiver set 353, 354, 355. A power system such as motors371, 372, and 373 connected to the seat for moving the base of the seat,a control unit such as a control circuit, system or module 254 connectedto the motors and a headrest actuation mechanism using servomotors 374and 375, which may be servomotors, are also illustrated. The seat 4 andheadrest 356 are shown in phantom. Vertical motion of the headrest 356is accomplished when a signal is sent from control module 254 toservomotor 374 through a wire 376. Servomotor 374 rotates lead screw 377which engages with a threaded hole in member 378 causing it to move upor down depending on the direction of rotation of the lead screw 377.Headrest support rods 379 and 380 are attached to member 378 and causethe headrest 356 to translate up or down with member 378. In thismanner, the vertical position of the headrest can be controlled asdepicted by arrow A-A. Ultrasonic transmitters and receivers 353, 354,355 may be replaced by other appropriate wave-generating and receivingdevices, such as electromagnetic, active infrared transmitters andreceivers, and capacitance sensors and electric field sensors.

Wire 381 leads from control module 254 to servomotor 375 which rotateslead screw 382. Lead screw 382 engages with a threaded hole in shaft 383which is attached to supporting structures within the seat shown inphantom. The rotation of lead screw 382 rotates servo motor support 384,upon which servomotor 374 is situated, which in turn rotates headrestsupport rods 379 and 380 in slots 385 and 386 in the seat 4. Rotation ofthe servomotor support 384 is facilitated by a rod 387 upon which theservo motor support 384 is positioned. In this manner, the headrest 356is caused to move in the fore and aft direction as depicted by arrowB-B. There are other designs which accomplish the same effect in movingthe headrest up and down and fore and aft.

The operation of the system is as follows. When an adult or childoccupant is seated on a seat containing the headrest and control systemdescribed above as determined by the neural network 65, the ultrasonictransmitters 353, 354 and 355 emit ultrasonic energy which reflects offof the head of the occupant and is received by the same transducers. Anelectronic circuit in control module 254 contains a microprocessor whichdetermines the distance from the head of the occupant based on the timebetween the transmission and reception of the ultrasonic pulses. In theembodiment wherein capacitance or electric field sensors are usedinstead of ultrasonic transducers, the manner in which the distance canbe determined using such sensors is known to those skilled in the art.

Control module 254 may be within the same microprocessor as neuralnetwork 65 or separate therefrom. The headrest 356 moves up and downuntil it finds the top of the head and then the vertical positionclosest to the head of the occupant and then remains at that position.Based on the time delay between transmission and reception of anultrasonic pulse, the system can also determine the longitudinaldistance from the headrest to the occupant's head. Since the head maynot be located precisely in line with the ultrasonic sensors, or theoccupant may be wearing a hat, coat with a high collar, or may have alarge hairdo, there may be some error in this longitudinal measurement.

When an occupant sits on seat 4, the headrest 356 moves to find the topof the occupant's head as discussed above. This is accomplished using analgorithm and a microprocessor which is part of control circuit 254. Theheadrest 356 then moves to the optimum location for rear impactprotection as described in the '320 patent. Once the height of theoccupant has been measured, another algorithm in the microprocessor incontrol circuit 254 compares the occupant's measured height with a tablerepresenting the population as a whole and from this table, theappropriate positions for the seat corresponding to the occupant'sheight is selected. For example, if the occupant measured 33 inches fromthe top of the seat bottom, this might correspond to an 85% human,depending on the particular seat and statistical table of humanmeasurements.

Careful study of each particular vehicle model provides the data for thetable of the location of the seat to properly position the eyes of theoccupant within the “eye-ellipse”, the steering wheel within acomfortable reach of the occupant's hands and the pedals within acomfortable reach of the occupant's feet, based on his or her size, etc.Of course one or more pedals can be manually adjusted providing they areprovided with an actuator such as an electric motor and any suchadjustment, either manual or automatic, is contemplated by theinventions disclosed herein.

Once the proper position has been determined by control circuit 254,signals are sent to motors 371, 372, and 373 to move the seat to thatposition, if such movement is necessary. That is, it is possible thatthe seat will be in the proper position so that movement of the seat isnot required. As such, the position of the motors 371, 372, 373 and/orthe position of the seat prior to occupancy by the occupant may bestored in memory so that after occupancy by the occupant anddetermination of the desired position of the seat, a comparison is madeto determine whether the desired position of the seat deviates from thecurrent position of the seat. If not, movement of the seat is notrequired. Otherwise, the signals are sent by the control circuit 254 tothe motors. In this case, control circuit 254 would encompass a seatcontroller.

Instead of adjusting the seat to position the driver in an optimumdriving position, or for use when adjusting the seat of a passenger, itis possible to perform the adjustment with a view toward optimizing theactuation or deployment of an occupant protection or restraint device.For example, after obtaining one or more morphological characteristicsof the occupant, the processor can analyze them and determine one ormore preferred positions of the seat, with the position of the seatbeing related to the position of the occupant, so that if the occupantprotection device is deployed, the occupant will be in an advantageousposition to be protected against injury by such deployment. In this casethen, the seat is adjusted based on the morphology of the occupant viewa view toward optimizing deployment of the occupant protection device.The processor is provided in a training or programming stage with thepreferred seat positions for different morphologies of occupants.

Movement of the seat can take place either immediately upon the occupantsitting in the seat or immediately prior to a crash requiring deploymentof the occupant protection device. In the latter case, if ananticipatory sensing arrangement is used, the seat can be positionedimmediately prior to the impact, much in a similar manner as theheadrest is adjusted for a rear impact as disclosed in the '320 patent.

If during some set time period after the seat has been positioned, theoperator changes these adjustments, the new positions of the seat arestored in association with an occupant height class in a second tablewithin control circuit 254. When the occupant again occupies the seatand his or her height has once again been determined, the controlcircuit 254 will find an entry in the second table which takesprecedence over the basic, original table and the seat returns to theadjusted position. When the occupant leaves the vehicle, or even whenthe engine is shut off and the door opened, the seat can be returned toa neutral position which provides for easy entry and exit from thevehicle.

The seat 4 also contains two control switch assemblies 388 and 389 formanually controlling the position of the seat 4 and headrest 356. Theseat control switches 388 permits the occupant to adjust the position ofthe seat if he or she is dissatisfied with the position selected by thealgorithm. The headrest control switches 389 permit the occupant toadjust the position of the headrest in the event that the calculatedposition is uncomfortably close to or far from the occupant's head. Awoman with a large hairdo might find that the headrest automaticallyadjusts so as to contact her hairdo. This adjustment she might findannoying and could then position the headrest further from her head. Forthose vehicles which have a seat memory system for associating the seatposition with a particular occupant, which has been assumed above, theposition of the headrest relative to the occupant's head could also berecorded. Later, when the occupant enters the vehicle, and the seatautomatically adjusts to the recorded preference, the headrest willsimilarly automatically adjust.

The height of the occupant, although probably the best initialmorphological characteristic, may not be sufficient especially fordistinguishing one driver from another when they are approximately thesame height. A second characteristic, the occupant's weight, can also bereadily determined from sensors mounted within the seat in a variety ofways as shown in FIGS. 42-49 of the '934 application.

Displacement sensor 159 is supported from supports 165. In general,displacement sensor 164, or another non-displacement sensor, measures aphysical state of a component affected by the occupancy of the seat. Anoccupying item of the seat will cause a force to be exerted downward andthe magnitude of this force is representative of the weight of theoccupying item. Thus, by measuring this force, information about theweight of the occupying item can be obtained. A physical state may beany force changed by the occupancy of the seat and which is reflected inthe component, e.g., strain of a component, compression of a component,tension of a component. Other weight measuring systems as describedherein and elsewhere including bladders and strain gages can be used.

An alternative approach is to measure the load on the vehicle suspensionsystem while the vehicle is at rest (static) or when it is in motion(dynamic). The normal empty state of the vehicle can be determined whenthe vehicle is at rest for a prolonged time period. After then thenumber and location of occupying items can be determined by measuringthe increased load on the suspension devices that attach the vehiclebody to its frame. SAW strain measuring elements can be placed on eachsuspension spring, for example, and used to measure the increased loadon the vehicle as an object or occupant is placed in the vehicle. Thisapproach has the advantage that it is not affected by seatbelt loadings,for example. If the vehicle is monitored as each item is paced in thevehicle a characterization of that item can be made. The taking on offuel, for example, will correspond to a particular loading pattern overtime that will permit the identification of the amount of the weight onthe suspension that can be attributed to fuel. Dynamic measuring systemsare similar to those used in section 6.3 and thus will not be repeatedhere.

The system described above is based on the assumption that the occupantwill be satisfied with one seat position throughout an extended drivingtrip. Studies have shown that for extended travel periods that thecomfort of the driver can be improved through variations in the seatposition. This variability can be handled in several ways. For example,the amount and type of variation preferred by an occupant of theparticular morphology can be determined through case studies and focusgroups. If it is found, for example, that the 50 percentile male driverprefers the seat back angle to vary by 5 degrees sinusodially with aone-hour period, this can be programmed to the system. Since the systemknows the morphology of the driver it can decide from a lookup tablewhat is the best variability for the average driver of that morphology.The driver then can select from several preferred possibilities if, forexample, he or she wishes to have the seat back not move at all orfollow an excursion of 10 degrees over two hours.

This system provides an identification of the driver based on twomorphological characteristics which is adequate for most cases. Asadditional features of the vehicle interior identification andmonitoring system described in above-referenced patent applications areimplemented, it will be possible to obtain additional morphologicalmeasurements of the driver which will provide even greater accuracy indriver identification. Such additional measurements include iris scans,voice prints, face recognition, fingerprints, voiceprints hand or palmprints etc. Two characteristics may not be sufficient to rely on fortheft and security purposes, however, many other driver preferences canstill be added to seat position with this level of occupant recognitionaccuracy. These include the automatic selection of a preferred radiostation, pedal position, vehicle temperature, steering wheel andsteering column position, etc.

One advantage of using only the height and weight is that it avoids thenecessity of the seat manufacturer from having to interact with theheadliner manufacturer, or other component suppliers, since all of themeasuring transducers are in the seat. This two characteristic system isgenerally sufficient to distinguish drivers that normally drive aparticular vehicle. This system costs little more than the memorysystems now in use and is passive, i.e., it does not require action onthe part of the occupant after his initial adjustment has been made.

Instead of measuring the height and weight of the occupant, it is alsopossible to measure a combination of any two morphologicalcharacteristics and during a training phase, derive a relationshipbetween the occupancy of the seat, e.g., adult occupant, child occupant,etc., and the data of the two morphological characteristic. Thisrelationship may be embodied within a neural network so that during use,by measuring the two morphological characteristics, the occupancy of theseat can be determined.

There are other methods of measuring the height of the driver such asplacing the transducers at other locations in the vehicle. Somealternatives are shown in other figures herein and include partial sideimages of the occupant and ultrasonic transducers positioned on or nearthe vehicle headliner. These transducers may already be present becauseof other implementations of the vehicle interior identification andmonitoring system described in above-referenced patent applications. Theuse of several transducers provides a more accurate determination oflocation of the head of the driver. When using a headliner mountedsensor alone, the exact position of the head is ambiguous since thetransducer measures the distance to the head regardless of whatdirection the head is. By knowing the distance from the head to anotherheadliner mounted transducer the ambiguity is substantially reduced.This argument is of course dependent on the use of ultrasonictransducers. Optical transducers using CCD, CMOS or equivalent arraysare now becoming price competitive and, as pointed out inabove-referenced patent applications, will be the technology of choicefor interior vehicle monitoring. A single CMOS array of 160 by 160pixels, for example, coupled with the appropriate pattern recognitionsoftware, can be used to form an image of the head of an occupant andaccurately locate the head for the purposes of at least one of theinventions disclosed herein. It can also be used with a face recognitionalgorithm to positively identify the occupant.

FIG. 34 also illustrates a system where the seatbelt 27 has anadjustable upper anchorage point 390 which is automatically adjusted bya motor 391 to a location optimized based on the height of the occupant.In this system, infrared transmitter and CCD array receivers 6 and 9 arepositioned in a convenient location proximate the occupant's shoulder,such as in connection with the headliner, above and usually to theoutside of the occupant's shoulder. An appropriate pattern recognitionsystem, as may be resident in control circuitry 20 to which thereceivers 6 and 9 are coupled, as described above is then used todetermine the location and position of the shoulder. This information isprovided by control circuitry 20 to the seatbelt anchorage heightadjustment system 391 (through a conventional coupling arrangement),shown schematically, which moves the attachment point 390 of theseatbelt 27 to the optimum vertical location for the proper placement ofthe seatbelt 27.

The calculations for this feature and the appropriate control circuitrycan also be located in control module 20 or elsewhere if appropriate.Seatbelts are most effective when the upper attachment point to thevehicle is positioned vertically close to the shoulder of the occupantbeing restrained. If the attachment point is too low, the occupantexperiences discomfort from the rubbing of the belt on his or hershoulder. If it is too high, the occupant may experience discomfort dueto the rubbing of the belt against his or her neck and the occupant willmove forward by a greater amount during a crash which may result in hisor her head striking the steering wheel. For these reasons, it isdesirable to have the upper seatbelt attachment point located slightlyabove the occupant's shoulder. To accomplish this for various sizedoccupants, the location of the occupant's shoulder should be known,which can be accomplished by the vehicle interior monitoring systemdescribed herein.

Many luxury automobiles today have the ability to control the angle ofthe seat back as well as a lumbar support. These additional motions ofthe seat can also be controlled by the seat adjustment system inaccordance with the invention. FIG. 35 is a view of the seat of FIG. 28showing motors 392 and 393 for changing the tilt of the seat back andthe lumbar support. Three motors 393 are used to adjust the lumbarsupport in this implementation. The same procedure is used for theseadditional motions as described for FIG. 28 above.

An initial table is provided based on the optimum positions for varioussegments of the population. For example, for some applications the tablemay contain a setting value for each five percentile of the populationfor each of the 6 possible seat motions, fore and aft, up and down,total seat tilt, seat back angle, lumbar position, and headrest positionfor a total of 120 table entries. The second table similarly wouldcontain the personal preference modified values of the 6 positionsdesired by a particular driver.

The angular resolution of a transducer is proportional to the ratio ofthe wavelength to the diameter of the transmitter. Once threetransmitters and receivers are used, the approximate equivalent singletransmitter and receiver is one which has a diameter approximately equalto the shortest distance between any pair of transducers. In this case,the equivalent diameter is equal to the distance between transmitter 354or 355 and 353. This provides far greater resolution and, by controllingthe phase between signals sent by the transmitters, the direction of theequivalent ultrasonic beam can be controlled. Thus, the head of thedriver can be scanned with great accuracy and a map made of theoccupant's head. Using this technology plus an appropriate patternrecognition algorithm, such as a neural network, an accurate location ofthe driver's head can be found even when the driver's head is partiallyobscured by a hat, coat, or hairdo. This also provides at least oneother identification morphological characteristic which can be used tofurther identify the occupant, namely the diameter of the driver's head.

In an automobile, there is an approximately fixed vertical distancebetween the optimum location of the occupant's eyes and the location ofthe pedals. The distant from a driver's eyes to his or her feet, on theother hand, is not the same for all people. An individual driver nowcompensates for this discrepancy by moving the seat and by changing theangle between his or hers legs and body. For both small and largedrivers, this discrepancy cannot be fully compensated for and as aresult, their eyes are not appropriately placed. A similar problemexists with the steering wheel. To help correct these problems, thepedals and steering column should be movable as illustrated in FIG. 36which is a plan view similar to that of FIG. 34 showing a driver anddriver seat with an automatically adjustable steering column and pedalsystem which is adjusted based on the morphology of the driver.

In FIG. 36, a motor 394 is connected to and controls the position of thesteering column and another motor 395 is connected to and controls theposition of the pedals. Both motors 394 and 395 are coupled to andcontrolled by control circuit 254 wherein now the basic table ofsettings includes values for both the pedals and steering columnlocations.

The settings may be determined through experimentation or empirically bydetermining an optimum position of the pedals and steering wheel fordrivers having different morphologies, i.e., different heights,different leg lengths, etc.

Although movement of the steering wheel is shown here as beingcontrolled by a motor 394 that moves the steering column fore and aft,other methods are sometimes used in various vehicles such as changingthe tilt angle of the steering column or the tilt angle of the steeringwheel. Motors can be provided that cause these other motions and arecontemplated by at least one of the inventions disclosed herein as isany other method that controls the position of the steering wheel.

Regardless of which motor or motors are used, the invention contemplatesthe adjustment or movement of the steering wheel relative to the frontconsole of the vehicle and thus relative to the driver of the vehicle.This movement may be directly effective on the steering wheel oreffective on the steering column and thus indirectly effective on thesteering wheel since movement of the steering column will cause movementof the steering wheel. Additionally when the ignition is turned off thesteering wheel and column and any other adjustable device or componentcan be automatically moved to a more out of the way position to permiteasier ingress and egress from the vehicle, for example.

The steering wheel adjustment feature may be designed to be activatedupon detection of the presence of an object on the driver's seat. Thus,when a driver's first sits on the seat, the sensors could be designed toinitiate measurement of the driver's morphology and then control themotor or motors to adjust the steering wheel, if such adjustment isdeemed necessary. This is because an adjustment in the position of thesteering wheel is usually not required during the course of driving butis generally only required when a driver first sits in the seat. Thedetection of the presence of the driver may be achieved using the weightsensors and/or other presence detection system, such as using thewave-based sensors, capacitance sensors, electric field sensors, etc.

The eye ellipse discussed above is illustrated at 358 in FIG. 37, whichis a view showing the occupant's eyes and the seat adjusted to place theeyes at a particular vertical position for proper viewing through thewindshield and rear view mirror. Many systems are now under developmentto improve vehicle safety and driving ease. For example, night visionsystems are being sold which project an enhanced image of the road aheadof the vehicle onto the windshield in a “heads-up display”. The mainproblem with the systems now being sold is that the projected image doesnot precisely overlap the image as seen through the windshield. Thisparallax causes confusion in the driver and can only be corrected if thelocation of the driver's eyes is accurately known. One method of solvingthis problem is to use the passive seat adjustment system describedherein to place the occupant's eyes at the optimum location as describedabove. Once this has been accomplished, in addition to solving theparallax problem, the eyes are properly located with respect to the rearview mirror 55 and little if any adjustment is required in order for thedriver to have the proper view of what is behind the vehicle. Currentlythe problem is solved by projecting the heads-up display onto adifferent portion of the windshield, the bottom.

Although it has been described herein that the seat can be automaticallyadjusted to place the driver's eyes in the “eye-ellipse”, there are manymanual methods that can be implemented with feedback to the drivertelling him or her when his or her eyes are properly position. At leastone of the inventions disclosed herein is not limited by the use ofautomatic methods.

Once the morphology of the driver and the seat position is known, manyother objects in the vehicle can be automatically adjusted to conform tothe occupant. An automatically adjustable seat armrest, a cup holder,the cellular phone, or any other objects with which the driver interactscan be now moved to accommodate the driver. This is in addition to thepersonal preference items such as the radio station, temperature, etc.discussed above.

Once the system of at least one of the inventions disclosed herein isimplemented, additional features become possible such as a seat whichautomatically makes slight adjustments to help alleviate fatigue or toaccount for a change of position of the driver in the seat, or a seatwhich automatically changes position slightly based on the time of day.Many people prefer to sit more upright when driving at night, forexample. Other similar improvements based on knowledge of the occupantmorphology will now become obvious to those skilled in the art.

Although several preferred embodiments are illustrated and describedabove, there are other possible combinations using different sensorswhich measure either the same or different morphologicalcharacteristics, such as knee position, of an occupant to accomplish thesame or similar goals as those described herein.

It should be mentioned that the adjustment system may be used inconjunction with each vehicle seat. In this case, if a seat isdetermined to be unoccupied, then the processor may be designed toadjust the seat for the benefit of other occupants, i.e., if a frontpassenger side seat is unoccupied but the rear passenger side seat isoccupied, then adjustment system could adjust the front seat for thebenefit of the rear-seated passenger, e.g., move the seat base forward.

In additional embodiments, the present invention involves themeasurement of one or more morphological characteristics of a vehicleoccupant and the use of these measurements to classify the occupant asto size and weight, and then to use this classification to position avehicle component, such as the seat, to a near optimum position for thatclass of occupant. Additional information concerning occupantpreferences can also be associated with the occupant class so that whena person belonging to that particular class occupies the vehicle, thepreferences associated with that class are implemented. Thesepreferences and associated component adjustments include the seatlocation after it has been manually adjusted away from the positionchosen initially by the system, the mirror location, temperature, radiostation, steering wheel and steering column positions, pedal positionsetc. The preferred morphological characteristics used are the occupantheight from the vehicle seat, weight of the occupant and facialfeatures. The height is determined by sensors, usually ultrasonic orelectromagnetic, located in the headrest, headliner or anotherconvenient location. The weight is determined by one of a variety oftechnologies that measure either pressure on or displacement of thevehicle seat or the force in the seat supporting structure. The facialfeatures are determined by image analysis comprising an imager such as aCCD or CMOS camera plus additional hardware and software.

The eye tracker systems discussed above are facilitated by at least oneof the inventions disclosed herein since one of the main purposes ofdetermining the location of the driver's eyes either by directlylocating them with trained pattern recognition technology or byinferring their location from the location of the driver's head, is sothat the seat can be automatically positioned to place the driver's eyesinto the “eye-ellipse”. The eye-ellipse is the proper location for thedriver's eyes to permit optimal operation of the vehicle and for thelocation of the mirrors etc. Thus, if the location of the driver's eyesare known, then the driver can be positioned so that his or her eyes areprecisely situated in the eye ellipse and the reflection off of the eyecan be monitored with a small eye tracker system. Also, by ascertainingthe location of the driver's eyes, a rear view mirror positioning devicecan be controlled to adjust the mirror 55 to an optimal position. Seesection 6.5.

13.3 Side Impacts

Side impact airbags are now used on some vehicles. Details about theincorporation of inventions disclosed herein for side impact airbagdeployment control are set forth in the '996 application, section 13.3,with reference to FIG. 38.

13.4 Children and Animals Left Alone

The various occupant sensing systems described herein can be used todetermine if a child or animal has been left alone in a vehicle and thetemperature is increasing or decreasing to where the child's or animal'shealth is at risk. When such a condition is discovered, the owner or anauthority can be summoned for help or, alternately, the vehicle enginecan be started and the vehicle warmed or cooled as needed. See section9.4.

13.5 Vehicle Theft

If a vehicle is stolen then several options are available when theoccupant sensing system is installed. Upon command by the owner over atelematics system, a picture of the vehicles interior can be taken andtransmitted to the owner. Alternately a continuous flow of pictures canbe sent over the telematics system along with the location of thevehicle if a GPS system is available or from the cell phone otherwise tohelp the owner or authorities determine where the vehicle is.

13.6 Security, Intruder Protection

If the owner has parked the vehicle and is returning, and an intruderhas entered and is hiding, that fact can be made known to the ownerbefore he or she opens the vehicle door. This can be accomplishedthought a wireless transmission to any of a number of devices that havebeen programmed for that function such as vehicle remote key fob, cellphones, PDAs etc.

13.7 Entertainment System Control

It is well known among acoustics engineers that the quality of soundcoming from an entertainment system can be substantially affected by thecharacteristics and contents of the space in which it operates and thesurfaces surrounding that space. When an engineer is designing a systemfor an automobile he or she has a great deal of knowledge about thatspace and of the vehicle surfaces surrounding it. He or she has littleknowledge of how many occupants are likely to be in the vehicle on aparticular day, however, and therefore the system is a compromise. Ifthe system knew the number and position of the vehicle occupants, andmay be even their size, then adjustments could be made in the systemoutput and the sound quality improved. FIG. 8A, therefore, illustratesschematically the interface between the vehicle interior monitoringsystem of at least one of the inventions disclosed herein, i.e.,transducers 49-52 and 54 and processor 20 which operate as set forthabove, and the vehicle entertainment system 99. The particular design ofthe entertainment system that uses the information provided by themonitoring system can be determined by those skilled in the appropriateart. Perhaps in combination with this system, the quality of the soundsystem can be measured by the audio system itself either by using thespeakers as receiving units also or through the use of specialmicrophones. The quality of the sound can then be adjusted according tothe vehicle occupancy and the reflectivity, or absorptivity, of thevehicle occupants. If, for example, certain frequencies are beingreflected, or absorbed, more than others, the audio amplifier can beadjusted to amplify those frequencies to a lesser, or greater, amountthan others.

The acoustic frequencies that are practical to use for acoustic imagingin the systems are between 40 to 160 kilohertz (kHz). The wavelength ofa 50 kHz acoustic wave is about 0.6 cm which is too coarse to determinethe fine features of a person's face, for example. It is well understoodby those skilled in the art that features which are smaller than thewavelength of the illuminating radiation cannot be distinguished.Similarly the wave length of common radar systems varies from about 0.9cm (for 33,000 MHz K band) to 133 cm (for 225 MHz P band) which is alsotoo coarse for person identification systems. In FIG. 4, therefore, theultrasonic transducers of the previous designs are replaced by lasertransducers 8 and 9 which are connected to a microprocessor 20. In allother manners, the system operates similarly. The design of theelectronic circuits for this laser system is described in U.S. Pat. No.5,653,462 and in particular FIG. 8 thereof and the correspondingdescription. In this case, a pattern recognition system such as a neuralnetwork system is employed and uses the demodulated signals from thereceptors 8 and 9. The output of processor 20 of the monitoring systemis shown connected schematically to a general interface 36 which can bethe vehicle ignition enabling system; the entertainment system; theseat, mirror, suspension or other adjustment systems; or any otherappropriate vehicle system.

Recent developments in the field of directing sound using hyper-sound(also referred to as hypersonic sound) now make it possible toaccurately direct sound to the vicinity of the ears of an occupant sothat only that occupant can hear the sound. The system of at least oneof the inventions disclosed herein can thus be used to find theproximate direction of the ears of the occupant for this purpose. Thisis discussed in the '996 application, section 13.7.

13.8 HVAC

In normal use (other than after a crash), the system determines whetherany human occupants are present, i.e., adults or children, and thelocation determining system 152 determines the occupant's location. Theprocessor 152 receives signals representative of the presence ofoccupants and their location and determines whether the vehicularsystem, component or subsystem 155 can be modified to optimize itsoperation for the specific arrangement of occupants. For example, if theprocessor 153 determines that only the front seats in the vehicle areoccupied, it could control the heating system to provide heat onlythrough vents situated to provide heat for the front-seated occupants.

Additional details of this aspect of the invention are set forth in the'996 application, section 13.8.

13.9 Obstruction Sensing

To the extent that occupant monitoring transducers can locate and trackparts of an occupant, this system can also be used to prevent arms,hands, fingers or heads from becoming trapped in a closing window ordoor. Although specific designs are presented for window and dooranti-trap solutions, if there are several imagers in the vehicle, thesesame imagers can monitor the various vehicle openings such as thewindows, sunroof, doors, trunk lid, hatchback door etc. In some cases,the system can be aided through the use of special lighting designs thateither cover only the opening or comprise structured light so that thedistance to a reflecting surface in or near to an opening can bedetermined. Additional details of obstruction sensing can be found inthe '881 application.

13.10 Rear Impacts

Rear impact protection is also discussed herein. A rear-of-head detector423 is illustrated in FIG. 38. This detector 423, which can be one ofthe types described above, is used to determine the distance from theheadrest to the rearmost position of the occupant's head and totherefore control the position of the headrest so that it is properlypositioned behind the occupant's head to offer optimum support during arear impact. Although the headrest of most vehicles is adjustable, it israre for an occupant to position it properly if at all. Each year thereare in excess of 400,000 whiplash injuries in vehicle impactsapproximately 90,000 of which are from rear impacts (source: NationalHighway Traffic Safety Admin.). A properly positioned headrest couldsubstantially reduce the frequency of such injuries, which can beaccomplished by the head detector of at least one of the inventionsdisclosed herein. The head detector 423 is shown connected schematicallyto the headrest control mechanism and circuitry 424. This mechanism iscapable of moving the headrest up and down and, in some cases, rotatingit fore and aft.

13.11 Combined with SDM and Other Systems

The occupant position sensor in any of its various forms may beintegrated into the airbag system circuitry. This aspect is discussed inthe '996 application, section 13.11.

13.12 Exterior Monitoring

The same system can also be used for the detection of objects in theblind spots and other areas surrounding the vehicle. This aspect isdiscussed in the '996 application, section 13.12 with reference to FIGS.52 and 56-58 therein.

The information provided by the exterior monitoring system can becombined with the interior monitoring system in order to optimize bothsystems for the protection of the occupants.

Although several preferred embodiments are illustrated and describedabove, there are possible combinations using other signals and sensorsfor the components and different forms of the neural networkimplementation or different pattern recognition technologies thatperform the same functions which can be utilized in accordance with theinvention. Also, although the neural network and modular neural networkshave been described as an example of one means of pattern recognition,other pattern recognition means exist and still others are beingdeveloped which can be used to identify potential component failures bycomparing the operation of a component over time with patternscharacteristic of normal and abnormal component operation. In addition,with the pattern recognition system described above, the input data tothe system may be data which has been pre-processed rather than the rawsignal data either through a process called “feature extraction” or byvarious mathematical transformations. Also, any of the apparatus andmethods disclosed herein may be used for diagnosing the state ofoperation or a plurality of discrete components.

Although several preferred embodiments are illustrated and describedabove, there are possible combinations using other geometries, sensors,materials and different dimensions for the components that perform thesame functions. At least one of the inventions disclosed herein is notlimited to the above embodiments and should be determined by thefollowing claims. There are also numerous additional applications inaddition to those described above. Many changes, modifications,variations and other uses and applications of the subject inventionwill, however, become apparent to those skilled in the art afterconsidering this specification and the accompanying drawings whichdisclose the preferred embodiments thereof. All such changes,modifications, variations and other uses and applications which do notdepart from the spirit and scope of the invention are deemed to becovered by the invention which is limited only by the following claims.

1. A vehicle including a system for determining the presence of anobject in a passenger compartment of the vehicle, the system comprisinga first image receiver arranged at a first location in the vehicle forobtaining a first two-dimensional view of a portion of the passengercompartment including the object; a second image receiver arranged at asecond location in the vehicle for obtaining a second two-dimensionalview of the same portion of the passenger compartment, said second imagereceiver being arranged relative to said first image receiver such thatthree dimensions of the portion of the passenger compartment areencompassed by said first and second views, and a processor coupled tosaid first and second image receivers and that receives images from saidfirst and second image receivers and determines whether an object ispresent in the portion of the passenger compartment based on the imagesobtained from both said first image receiver and said second imagereceiver.
 2. The vehicle of claim 1, wherein said first receiver isarranged on an A-pillar of the vehicle and thereby provides vertical andtransverse information about the portion of the passenger compartment.3. The vehicle of claim 1, wherein said first receiver is arranged on aroof of the vehicle above a seat of the vehicle or on a headliner of thevehicle directly above the portion of the passenger compartment.
 4. Thevehicle of claim 1, wherein said second receiver is arranged on aheadliner of the vehicle at or proximate a center of a headliner of thevehicle.
 5. The vehicle of claim 1, wherein said second receiver isarranged on a headliner of the vehicle relative to the portion of thepassenger compartment.
 6. The vehicle of claim 1, further comprising areactive component, system or subsystem coupled to said processor, saidprocessor being arranged to control said reactive component, system orsubsystem based on the determination of whether an object is present inthe portion of the passenger compartment.
 7. The vehicle of claim 6,wherein said reactive component, system or subsystem is an airbagassembly including at least one airbag, said processor being arranged tocontrol at least one deployment parameter of said at least one airbag.8. The vehicle of claim 1, wherein at least one of said first and secondreceivers is a CMOS dynamic pixel camera, an active pixel camera or anHDRC camera operative using a logarithm of incident light.
 9. Thevehicle of claim 1, wherein one of said first and second receivers isarranged in a dashboard or instrument panel of the vehicle to receive animage reflected by a windshield of the vehicle.
 10. The vehicle of claim1, wherein said processor is arranged to analyze the images from saidfirst and second image receivers over time by comparing the imagesreceived from each of said first and second receivers at different timeand analyzing differences between the images.
 11. A vehicle including asystem for ascertaining the identity of an object in a passengercompartment of the vehicle, the system comprising a first image receiverarranged at a first location in the vehicle for obtaining a firsttwo-dimensional view of a portion of the passenger compartment includingthe object; a second image receiver arranged at a second location in thevehicle for obtaining a second two-dimensional view of the same portionof the passenger compartment, said second image receiver being arrangedrelative to said first image receiver such that three dimensions of theportion of the passenger compartment are encompassed by said first andsecond images; and a processor coupled to said first and second imagereceivers and that receives images from said first and second imagereceivers and ascertains the identity of the object based on the imagesobtained from both said first image receiver and said second imagereceiver.
 12. The vehicle of claim 11, further comprising a reactivecomponent, system or subsystem coupled to said processor, said processorbeing arranged to control said reactive component, system or subsystembased on the identity of the object.
 13. The vehicle of claim 11,wherein said processor is arranged to analyze the images from said firstand second image receivers over time by comparing the images receivedfrom each of said first and second receivers at different time andanalyzing differences between the images.
 14. A method for determiningthe presence of an object in a passenger compartment of a vehicle,comprising: obtaining using a first imaging system, a first image of aportion of the passenger compartment covering first and seconddimensions of the passenger compartment, obtaining using a secondimaging system, a second image of the same portion of the passengercompartment covering the first dimension and a third dimension of thepassenger compartment such that three dimensions of the portion of thepassenger compartment are encompassed by the first and second imagesobtained by the first and second imaging systems, and determining usinga processor, whether an object is present in the passenger compartmentbased on the first and second images obtained by the first and secondimaging systems.
 15. The method of claim 14, wherein the first imagingsystem comprises a first receiver and the second imaging systemcomprises a second receiver, further comprising: arranging the firstreceiver to provide two-dimensional views of the portion of thepassenger compartment; and arranging the second receiver to provide adifferent two-dimensional view of the portion of the passengercompartment.
 16. The method of claim 14, further comprising: controllingusing a control system, a reactive component, system or subsystem basedon the determination by the processor of whether an object is present inthe portion of the passenger compartment.
 17. A method for ascertainingthe identity of an object in a passenger compartment of a vehicle,comprising: obtaining using a first imaging system, a first image of aportion of the passenger compartment covering first and seconddimensions of the passenger compartment; obtaining using a first imagingsystem, a second image of the same portion of the passenger compartmentcovering the first dimension and a third dimension of the passengercompartment such that all three dimensions of the portion of thepassenger compartment are encompassed by the first and second imagesobtained by the first and second imaging systems; and ascertaining usinga processor, the identity of the object in the passenger compartmentbased on the first and second images obtained by the first and secondimaging systems.
 18. The method of claim 17, wherein the first imagingsystem comprises a first receiver and the second imaging systemcomprises a second receiver, further comprising: arranging the firstreceiver to provide two-dimensional views of the portion of thepassenger compartment; and arranging the second receiver to provide adifferent two-dimensional view of the portion of the passengercompartment.
 19. The method of claim 17, further comprising: controllingusing a control system, a reactive component, system or subsystem basedon the identity of the object ascertained by the processor.
 20. Thevehicle of claim 1, further comprising: an airbag assembly including atleast one deployable airbag that deploys in an accident involving thevehicle to protect an occupant of the invention; and a crash sensorsystem arranged to sense an accident involving the vehicle, saidprocessor being coupled to aid airbag assembly and said crash sensorsystem and being arranged to control at least one deployment parameterof said at least one airbag based on sensing of an accident by saidcrash sensor system and the determination of whether an object ispresent in the portion of the passenger compartment.
 21. The vehicle ofclaim 1, wherein said processor includes a trained pattern recognitionalgorithm that is trained to determine whether an object is present inthe portion of the passenger compartment based on the images obtainedfrom both said first image receiver and said second image receiver. 22.The vehicle of claim 11, further comprising: an airbag assemblyincluding at least one deployable airbag that deploys in an accidentinvolving the vehicle to protect an occupant of the invention; and acrash sensor system arranged to sense an accident involving the vehicle,said processor being coupled to aid airbag assembly and said crashsensor system and being arranged to control at least one deploymentparameter of said at least one airbag based on sensing of an accident bysaid crash sensor system and the identity of object in the portion ofthe passenger compartment.
 23. The vehicle of claim 11, wherein saidprocessor includes a trained pattern recognition algorithm that istrained to ascertain the identity of the object based on the imagesobtained from both said first image receiver and said second imagereceiver.